Polycarpus takes part in the "Field of Wonders" TV show. The participants of the show have to guess a hidden word as fast as possible. Initially all the letters of the word are hidden.

The game consists of several turns. At each turn the participant tells a letter and the TV show host responds if there is such letter in the word or not. If there is such letter then the host reveals all such letters. For example, if the hidden word is "abacaba" and the player tells the letter "a", the host will reveal letters at all positions, occupied by "a": 1, 3, 5 and 7 (positions are numbered from left to right starting from 1).

Polycarpus knows m words of exactly the same length as the hidden word. The hidden word is also known to him and appears as one of these m words.

At current moment a number of turns have already been made and some letters (possibly zero) of the hidden word are already revealed. Previously Polycarp has told exactly the letters which are currently revealed.

It is Polycarpus' turn. He wants to tell a letter in such a way, that the TV show host will assuredly reveal at least one more letter. Polycarpus cannot tell the letters, which are already revealed.

Your task is to help Polycarpus and find out the number of letters he can tell so that the show host will assuredly reveal at least one of the remaining letters.

Input

The first line contains one integer n (1 ≤ n ≤ 50) — the length of the hidden word.

The following line describes already revealed letters. It contains the string of length n, which consists of lowercase Latin letters and symbols "*". If there is a letter at some position, then this letter was already revealed. If the position contains symbol "*", then the letter at this position has not been revealed yet. It is guaranteed, that at least one letter is still closed.

The third line contains an integer m (1 ≤ m ≤ 1000) — the number of words of length n, which Polycarpus knows. The following m lines contain the words themselves — n-letter strings of lowercase Latin letters. All words are distinct.

It is guaranteed that the hidden word appears as one of the given m words. Before the current move Polycarp has told exactly the letters which are currently revealed.

Output

Output the single integer — the number of letters Polycarpus can tell so that the TV show host definitely reveals at least one more letter. It is possible that this number is zero.

Examples

Input

4
a**d
2
abcd
acbd


Output

2


Input

5
lo*er
2
lover
loser


Output

0


Input

3
a*a
2
aaa
aba


Output

1

Note

In the first example Polycarpus can tell letters "b" and "c", which assuredly will be revealed.

The second example contains no letters which can be told as it is not clear, which of the letters "v" or "s" is located at the third position of the hidden word.

In the third example Polycarpus exactly knows that the hidden word is "aba", because in case it was "aaa", then the second letter "a" would have already been revealed in one of previous turns.
      import java.util.*; 
                                            import java.math.*;
                                            import java.io.*;
                                            import java.text.DecimalFormat;
                                            import java.math.BigInteger;
                                            public class Main{
                                                //static int d=20;
                                                static long mod=1000000007 ;
                                                
                                                static ArrayList<ArrayList<Integer>> arr;
                                               // static long[] dp1,dp2;
                                                static int[] a;
                                                static int[] vis,num;
                                                static long max;
                                                static HashSet<String> hs;
                                                //static int flag,ans;
                                                static long max1,max2,ans1;
                                                
                                                static int flag=0;
                                                static int[] tin,tout,parent,level;
                                                static HashMap<Long,Integer> hm;
                                                static long[] dp1,dp2,dp3,dp4;
                                                   
                                                public static void main(String[] args)  throws IOException {
                                                    ///long start=System.currentTimeMillis();
                                                    boolean online =false;
                                                    String fileName = "B-small-attempt0";
                                                    PrintWriter out; 
                                                    if (online) {
                                                        s.init(new FileInputStream(new File("Downloads/"+fileName + ".in")));
                                                         out= new PrintWriter(new FileWriter(fileName + "out.txt"));
                                                    }
                                                     else {
                                                        s.init(System.in);   
                                                    
                                                        out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
                                                        //out= new PrintWriter(new FileWriter(fileName + "out.txt"));
                                                    }//r,b,y,g
                                                    int n=s.ni();
                                                    String a=s.ns();
                                                    int m=s.ni();
                                                    int[] alp=new int[26];
                                                    int ct=0;
                                                    HashSet<Integer> hs2=new HashSet<>();
                                                    for(int i=0;i<n;i++)
                                                        hs2.add(a.charAt(i)-'a');
                                                    for(int i=0;i<m;i++){
                                                        int flag=0;
                                                        String b=s.ns();
                                                        HashSet<Integer> hs=new HashSet<Integer>();
                                                        for(int j=0;j<n;j++){
                                                            if(a.charAt(j)!='*'){
                                                                if(a.charAt(j)!=b.charAt(j)){
                                                                    flag=1;
                                                                    break;
                                                                }
                                                            }
                                                            else{
                                                                if(hs2.contains(b.charAt(j)-'a')){
                                                                    flag=1;
                                                                    break;
                                                                }
                                                                hs.add(b.charAt(j)-'a');
                                                            }
                                                        }
                                                        if(flag==0){
                                                            ct++;
                                                            for(int x:hs)
                                                                alp[x]++;
                                                        }
                                                    }
                                                    int ans=0;
                                                    for(int i=0;i<26;i++){
                                                        if(alp[i]==ct)
                                                            ans++;
                                                    }
                                                    out.println(ans);
                                                    out.close();
                                                        
                                                      
                                                            
                                            
                                                }
                                               
                                                

                                                public static void union(int[] a,int x,int y){
                                                    int u=find(a,x);
                                                    int v=find(a,y);
                                                    a[v]=u;

                                                }
                                                public static int find(int[] a,int x){
                                                    if(a[x]!=x){
                                                        a[x]=find(a,a[x]);
                                                    }
                                                    return a[x];
                                                }
                                                public static int gcd(int a, int b){
                                                        if (a == 0) return b;
                                                        return gcd(b % a, a);
                                                }
                                                    
                                                public static void cfs(ArrayList<HashSet<Integer>> arr,int c,int p,int g,int[] vis){
                                                    vis[c]=1;
                                                    if(g!=-1){
                                                        if(!arr.get(c).contains(g)){
                                                            flag=1;
                                                            return;
                                                        }
                                                    }
                                                    for(int x:arr.get(c)){
                                                        if(x!=p && x!=g && vis[x]==0 ){
                                                            cfs(arr,x,c,p,vis);
                                                        }
                                                    }
         
                                                }
                                                                      //   public static void dfs(int u,int p){
                 //                            //       if(p>=0)
                 //                            //           tin[u]=tout[u]=tt++;
                 //                            //       if(p>=0)
                 //                            //           level[u]=level[p]+1;
                 //                            //       parent[u]=p;
                 //                            //       for(int x:arr.get(u)){
                 //                            //           if(x!=p){
                 //                            //               dfs(x,u);
                 //                            //               tout[u]=Math.max(tout[u],tout[x]);
                 //                            //           }
                 //                            //       }
                 //                            //       
                 //
                 //
                                             //   }
                                                public static int lca(int[][] p,int a,int b){
                                                    if(level[a]<level[b]){
                                                        int x=a;
                                                        a=b;
                                                        b=x;
                                                    }
                                                    int log=p[0].length;
                                                    for(int i=log-1;i>=0;i--){
                                                        if(1<<i<=level[a]-level[b]){
                                                            a=p[a][i];
                                                        }
                                                    }
                                                    if(a==b)
                                                        return a;
                                                    for(int i=log-1;i>=0;i--){
                                                        if(p[a][i]!=p[b][i]){
                                                            a=p[a][i];
                                                            b=p[b][i];
                                                        }
                                                    }
                                                    return p[a][0];
                 
                                                }
                                                public static int[][] par(int[] parent){
                                                    int n=arr.size();
                                                    int[][] p=new int[n][17];
                                                    for(int i=0;i<n;i++)
                                                        p[i][0]=parent[i];
                                                    for(int k=1;k<17;k++){
                                                        for(int i=0;i<n;i++){
                                                            if(p[i][k-1]>-1)
                                                                p[i][k]=p[p[i][k-1]][k-1];
                                                            else
                                                                p[i][k]=-1;
                                                        }
                                                    }
                                                    return p;
                                                }
                                                static class Edge implements Comparable<Edge>{
                                                       int from;
                                                        int to;
                                                        long cost;
                                                
                                                       public Edge(int from, int to, long weight) {
                                                           this.from = from;
                                                           this.to = to;
                                                           this.cost= weight;
                                                       }
                                                       public int compareTo(Edge o){
                                                            return (int)Math.signum(cost-o.cost); 
                                                       }

                                                }                               
                                                static class Node {
                                                    int start;
                                                    int end;
                                
                                                    int cost;
                                                    int updated;
                                
                                                    Node[] nodes;
                                
                                                    public Node(int start, int end) {
                                                        this.start = start;
                                                        this.end = end;
                                
                                                        if (start < end) {
                                                            int[] pos = {start, (start + end) / 2, end};
                                                            nodes = new Node[2];
                                                            for (int i = 0; i < 2; i++) {
                                                                nodes[i] = new Node(pos[i] + i, pos[i + 1]);
                                                            }
                                                        }
                                                    }
                                
                                                    public void update(int queryStart, int queryEnd, int value) {
                                                        if (queryEnd < start || end < queryStart) {
                                                            return;
                                                        }
                                
                                                        if (queryStart <= start && end <= queryEnd) {
                                                            cost += value;
                                                            updated += value;
                                                            return;
                                                        }
                                
                                                        propagate();
                                                        for (Node node: nodes) {
                                                            node.update(queryStart, queryEnd, value);
                                                        }
                                                    }
                                
                                                    public int query(int pos) {
                                                        if (pos < start || end < pos) {
                                                            return 0;
                                                        }
                                
                                                        if (start == end) {
                                                            return cost;
                                                        }
                                
                                                        propagate();
                                                        int ans = 0;
                                                        for (Node node: nodes) {
                                                            ans = Math.max(ans, node.query(pos));
                                                        }
                                                        return ans;
                                                    }
                                
                                                    public void propagate() {
                                                        if (updated != 0 && start < end) {
                                                            for (Node node: nodes) {
                                                                node.cost += updated;
                                                                node.updated += updated;
                                                            }
                                                            updated = 0;
                                                        }
                                                    }
                                                }
                                                public static double nthroot(int n, double A) {
                                                    return nthroot(n, A, 0.0000001);
                                                }
                                                public static double nthroot(int n, double A, double p) {
                                                    if(A < 0) {
                                                        System.err.println("A < 0");// we handle only real positive numbers
                                                        return -1;
                                                    } else if(A == 0) {
                                                        return 0;
                                                    }
                                                    double x_prev = A;
                                                    double x = A / n;  // starting "guessed" value...
                                                    while(Math.abs(x - x_prev) > p) {
                                                        x_prev = x;
                                                        x = ((n - 1.0) * x + A / Math.pow(x, n - 1.0)) / n;
                                                    }
                                                    return x;
                                                }
                                                
                                                static class item implements Comparable<item> {
                                                    int from,to,cost;
                                                    public item(int x,int y){
                                                        from=x;
                                                        to=y;
                                                        
                                                    }
                                                    public int compareTo(item o){
                                                        
                                                        return  o.cost-cost;
                                                    }
                                                    
                                                }
                                               
                                                public static void dfs2(int c,int p,int[] a){
                                                    //System.out.println(c+" "+p);
                                                   
                                                    
                                                    
                         
                                                }
                //public static void dfs(int x,int[] vis,Stack<Integer> st){
                                                //    vis[x]=1;
                                                //    ArrayList<Integer> arr2=arr.get(x);
                                                //    Collections.sort(arr2);
                                                //    for(int i=arr2.size()-1;i>=0;i--){
                                                //        int z=arr2.get(i);
                                                //        if(vis[z]==0)
                                                //            dfs(z,vis,st);
                                                //    }
                                                //    st.push(x);
                         //
                                                //}
                                                public static long gcd(long a, long b){
                                                        if (a == 0) return b;
                                                        return gcd(b % a, a);
                                                }
                                                    
                                                public static boolean check(long x){
                                                    if(x%4==0 || x%7==0 || x%11==0)
                                                        return true;
                                                    if(x<4 || x<7 || x<11)
                                                        return false;
                                                    if(x%2==0){
                                                        return check(x/2);
                                                    }
                                                    else
                                                        return check(x/2) && check((x+1)/2);
                                                }
                                                public static int angle(int x1,int x2,int x3,int y1,int y2,int y3){
                                                    long val=(y2-y1)*1L*(x3-x2)-(y3-y2)*1L*(x2-x1);
                                                    if(val<0)
                                                        return 1;
                                                    else if(val>0)
                                                        return -1;
                                                    else
                                                        return 0;
                                                }
                                                
                                                static class BIT{
                                                
                                                    int N;
                                                    long tree[];
                                                    
                                                    BIT(int N){
                                                        this.N = N;
                                                        tree = new long[N + 1];
                                                    }
                                                    
                                                    void update(int idx,long val){
                                                        while(idx <= N){
                                                            tree[idx]+=val;
                                                            idx += (idx & -idx);
                                                        }
                                                    }
                                                    
                                                    long query(int l,int r){
                                                        if(l == 1)
                                                            return read(r);
                                                        else
                                                            return read(r) - read(l-1);
                                                    }
                                                    
                                                    long read(int idx){
                                                        long sum = 0;
                                                        while(idx > 0){
                                                            sum += tree[idx];
                                                            idx -= (idx & -idx);
                                                        }
                                                        return sum;
                                                    }
                                                }
                                                public static boolean pal(String a){
                                                    int i=0;
                                                    int j=a.length()-1;
                                                    while(i<j){
                                                        if(a.charAt(i)!=a.charAt(j)){
                                                            return false;
                                                        }
                                                        i++;
                                                        j--;
                                                    }
                                                    return true;
                                                        
                                                }
                                                public static long find(long n,long k){
                                                    if(n==2){
                                                        if(k==1 || k==3)
                                                            return 1;
                                                        else
                                                            return 2;
                                                    }
                                                    long t=pow2(2,n,mod)-1;
                                                    long z=(t+1)/2;
                                                    if(k==z)
                                                        return n;
                                                    if(k<z)
                                                        return find(n-1,k);
                                                    else
                                                        return find(n-1,k-z);
                                                }
                                                public static long pow2(long a,long b,long mod){
                                                        
                                                        long ans=1;
                                                       // long z=b;
                                                        while(b>0){
                                                           
                                                            if(b%2==1)
                                                                ans=(a*ans)%mod;
                                                            a=(a*a)%mod;
                                                            b/=2;
                                                        }
                                                      
                                                        return  ans;
                                                }
                                                 public static long pow3(long a,long b){
                                                        
                                                        long ans=1;
                                                       // long z=b;
                                                        while(b>0){
                                                           
                                                            if(b%2==1)
                                                                ans=(a*ans);
                                                            a=(a*a);
                                                            b/=2;
                                                        }
                                                      
                                                        return  ans;
                                                }
                                                public static long fib(long n){
                                                    long[][]    f=new long[][]{{1L,1L},{1L,0}};
                                                    if(n==0)
                                                        return 0;
                                                    f=arrpow(f,n-1);
                                                    return f[0][0];
                                                }
                                                public static long[][] arrpow(long[][] a,long b){
                                                   
                                                        int n=a.length;
                                                      //  long z=b;
                                                        long[][] ans=new long[n][n];
                                                        for(int i=0;i<n;i++)
                                                            ans[i][i]=1L;
                                                        while(b>0){
                                                            
                                                            if(b%2==1)
                                                                ans=mul(a,ans);
                                                            a=mul(a,a);
                                                            b/=2;
                                                        }
                                                        
                                                        return  ans;
                                                }
                                                public static long[][] mul(long[][] a,long[][] b){
                                                    int n=a.length;
                                                    int m=b[0].length;
                                                    long[][] ans=new long[n][m];
                                                    if(n==2 && m==2 && b.length==2){
                                                        ans[0][0]=((a[0][0]*b[0][0])%mod+(a[0][1]*b[1][0]))%mod;
                                                        ans[0][1]=((a[0][0]*b[0][1])%mod+(a[0][1]*b[1][1]))%mod;
                                                        ans[1][0]=((a[1][0]*b[0][0])%mod+(a[1][1]*b[1][0]))%mod;
                                                        ans[1][1]=((a[1][1]*b[1][1])%mod+(a[1][0]*b[0][1]))%mod;
                                                        return ans;
                     
                                                    }
                                                    for(int i=0;i<n;i++){
                                                        for(int j=0;j<m;j++){
                                                            for(int k=0;k<b.length;k++){
                                                                ans[i][j]=(ans[i][j]+(a[i][k]*b[k][j])%mod)%mod;
                                                            }
                                                        }
                                                    }
                                                    return ans; 
                                                }
                                                 static class name implements Comparable<name> {
                                                    long l,b,h;
                                                    public name(long   x,long y,long z){
                                                        {
                                                            l=x;
                                                            b=y;        
                                                        }
                                                        
                                                        
                                                        h=z;
                                                    }
                                                    public int compareTo(name o){
                                                        return -(int)(l*b-o.l*o.b);
                                                    }
                                                    
                                                }
                                                public static class s {
                                                    static BufferedReader reader;
                                                    static StringTokenizer tokenizer;
                                                
                                                    /** call this method to initialize reader for InputStream */
                                                    static void init(InputStream input) {
                                                        reader = new BufferedReader(
                                                                    new InputStreamReader(input) );
                                                        tokenizer = new StringTokenizer("");
                                                    }   
                                                
                                                    /** get next word */
                                                    static String ns() throws IOException {
                                                        while ( ! tokenizer.hasMoreTokens() ) {
                                                            //TODO add check for eof if necessary
                                                            tokenizer = new StringTokenizer(
                                                                reader.readLine() );
                                                        }
                                                        return tokenizer.nextToken();
                                                    }
                                                
                                                    static int ni() throws IOException {
                                                        return Integer.parseInt( ns() );
                                                    }
                                                
                                                    static double nd() throws IOException {
                                                        return Double.parseDouble( ns() );
                                                    }
                                                    static long nl() throws IOException {
                                                        return Long.parseLong( ns() );
                                                    }
                                                }
                                            }   

