Caisa solved the problem with the sugar and now he is on the way back to home. 

Caisa is playing a mobile game during his path. There are (n + 1) pylons numbered from 0 to n in this game. The pylon with number 0 has zero height, the pylon with number i (i > 0) has height hi. The goal of the game is to reach n-th pylon, and the only move the player can do is to jump from the current pylon (let's denote its number as k) to the next one (its number will be k + 1). When the player have made such a move, its energy increases by hk - hk + 1 (if this value is negative the player loses energy). The player must have non-negative amount of energy at any moment of the time. 

Initially Caisa stand at 0 pylon and has 0 energy. The game provides a special opportunity: one can pay a single dollar and increase the height of anyone pylon by one. Caisa may use that opportunity several times, but he doesn't want to spend too much money. What is the minimal amount of money he must paid to reach the goal of the game?

Input

The first line contains integer n (1 ≤ n ≤ 105). The next line contains n integers h1, h2, ..., hn (1 ≤ hi ≤ 105) representing the heights of the pylons.

Output

Print a single number representing the minimum number of dollars paid by Caisa.

Examples

Input

5
3 4 3 2 4


Output

4


Input

3
4 4 4


Output

4

Note

In the first sample he can pay 4 dollars and increase the height of pylon with number 0 by 4 units. Then he can safely pass to the last pylon.


import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.util.Scanner; 
import java.util.StringTokenizer; 
import java.util.*;
import java.math.*;
  
public class er10a
{ 
    //By shwetank_verma
    static class FastReader 
    { 
        BufferedReader br; 
        StringTokenizer st; 
  
        public FastReader() 
        { 
            br = new BufferedReader(new
                     InputStreamReader(System.in)); 
        } 
  
        String next() 
        { 
            while (st == null || !st.hasMoreElements()) 
            { 
                try
                { 
                    st = new StringTokenizer(br.readLine()); 
                } 
                catch (IOException  e) 
                { 
                    e.printStackTrace(); 
                } 
            } 
            return st.nextToken(); 
        } 
  
        int nextInt() 
        { 
            return Integer.parseInt(next()); 
        } 
  
        long nextLong() 
        { 
            return Long.parseLong(next()); 
        } 
  
        double nextDouble() 
        { 
            return Double.parseDouble(next()); 
        } 
  
        String nextLine() 
        { 
            String str = ""; 
            try
            { 
                str = br.readLine(); 
            } 
            catch (IOException e) 
            { 
                e.printStackTrace(); 
            } 
            return str; 
        } 
    } 
    static int mod=(int)(1e9+7);
    static boolean primes[]=new boolean[1000007];
    static ArrayList<Integer> b=new ArrayList<>();
    static void seive(int n){
        Arrays.fill(primes,true);
        primes[0]=primes[1]=false;
        for(int i=2;i*i<=n;i++){
            if(primes[i]==true){
                for(int p=i*i;p<=n;p+=i){
                    primes[p]=false;
                }
            }
        }
        if(n<1000007){
        	for(int i=2;i<=n;i++) {
        		if(primes[i])
        			b.add(i);
        	}
        	
                 }
        
        
    }
    static int gcd(int a,int b){
        if(b==0)
        return a;
        return gcd(b,a%b);
    }
    static long GCD(long a,long b){
        if(b==0)
        return a;
        return GCD(b,a%b);
    }
    static ArrayList<Integer> segseive(int l,int r){
    	
    	ArrayList<Integer> isprime=new ArrayList<Integer>();
    	boolean p[]=new boolean[r-l+1];
    	Arrays.fill(p, true);
        
    	for(int i=0;b.get(i)*b.get(i)<=r;i++) {
    		int currprime=b.get(i);
    		int base=(l/currprime)*currprime;
    		if(base<l) {
    			base+=currprime;
    		}
    		for(int j=base;j<=r;j+=currprime) {
    			p[j-l]=false;
    		}
    		
    		
    		if(base==currprime) {
    			p[base-l]=true;
    		}
    		
    	}
    	for(int i=0;i<=r-l;i++) {
    		if(p[i])
    			isprime.add(i+l);
    	}
    	return isprime;
    }
      static int LowerBound(int a[], int x) { // x is the target value or key
  int l=-1,r=a.length;
  while(l+1<r) {
    int m=(l+r)>>>1;
    if(a[m]>=x) r=m;
    else l=m;
  }
  return r;
}
static int UpperBound(int a[], int x) {// x is the key or target value
    int l=-1,r=a.length;
    while(l+1<r) {
       int m=(l+r)>>>1;
       if(a[m]<=x) l=m;
       else r=m;
    }
    return l+1;
 }
 static void addEdge(ArrayList<ArrayList<Integer>> adj,int u,int v) {
	 adj.get(u).add(v);
	 adj.get(v).add(u);
 }
 static void BFS(ArrayList<ArrayList<Integer>> adj,int s,boolean visited[]) {
	 Queue<Integer> q=new LinkedList<>();
	 q.add(s);
	 visited[s]=true;
	 while(!q.isEmpty()) {
		 int u=q.poll();
		 for(int v:adj.get(u)) {
			 if(!visited[v]) {
				 visited[v]=!visited[v];
				 q.add(v);
			 }
		 }
	 }
 }
 static int BFSconnectedcount(ArrayList<ArrayList<Integer>> adj,int v) {
	 boolean visited[]=new boolean[v+1];
	 int count=0;
	 for(int i=0;i<v;i++) {
		 if(!visited[i]) {
			 BFS(adj,i,visited);
			 count++;
		 }
	 }
	 return count;
 }
 public static long power(long x, long y, long p) {
     long res = 1;
     x = x % p;
     while (y>0) {
        if ((y&1)==1) {
           res = (res*x) % p;
        }
        y = y >> 1;
        x = ( x * x ) % p;
     }
     return res;
  }
 public static long monInverse( long n, long p) {
     return power(n, p-2, p);
  }
  public static long nCrModPFermat( int n, int r, int p) {
     long[] fac = new long[n+1];
     fac[0] = 1;
     for (int i = 0; i < n; i++) {
        fac[i+1] = (fac[i]*(i+1))%p;
     }
long x = monInverse(fac[r], p);
long y = monInverse(fac[n-r], p);
//System.out.println(fac[n]);
     return (((fac[n]*x)% p) * ( y%p) ) % p;
  }
 static class Point
  {
      int x, y;
      Point(int x, int y)
      {
          this.x = x;
          this.y = y;
      }
  }

  // This class implements 
  // Comparator interface
  static class MyCmp implements Comparator<Point>
  {
      // Sorts the Point objects according
      // to x-coordinates in natural order
      public int compare(Point p1, Point p2)
      {
          return p1.x - p2.x;
      }
  }
  static int maxSubArraySum(int a[], int size) 
  { 
  int max_so_far = a[0]; 
  int curr_max = a[0]; 

  for (int i = 1; i < size; i++) 
  { 
         curr_max = Math.max(a[i], curr_max+a[i]); 
      max_so_far = Math.max(max_so_far, curr_max); 
  } 
  return max_so_far; 
  } 
  static int maxsum(int a[],int n) {
	  int s=0;
	  int res=0;
	  int sum[]=new int[n];
	  sum[0]=a[0];
	  for(int i=1;i<n;i++) {
	     sum[i]=sum[i-1]+a[i];
	  }
	  for(int i=0;i<n;i++) {
		  s=Math.max(s, sum[i]);
	  }
	  return s;
  }
 static void leftRotate(int arr[], 
          int d, int n) 
{ 
for (int i = 0; i < d; i++) 
  leftRotatebyOne(arr, n); 
} 

static void leftRotatebyOne(int arr[], int n) 
{ 
int i, temp; 
temp = arr[0]; 
for (i = 0; i < n - 1; i++) 
  arr[i] = arr[i + 1]; 
arr[i] = temp; 
} 
    public static void main(String[] args) 
    { 
        FastReader sc=new FastReader(); 
        int t=1;
        //t=sc.nextInt();
        
        while(t-->0) {
        	int n=sc.nextInt();
        	int a[]=new int[n+1];
        	for(int i=1;i<=n;i++) {
        		a[i]=sc.nextInt();
        		
        	}
        	Arrays.sort(a);
        	long d=0;
        	for(int i=0;i<n;i++) {
        		d+=a[i]-a[i+1];
        	}
        	if(d>=0)
        		System.out.println(0);
        	else
        		System.out.println(-d);
        }
    } 
    
}

