Alexandra has a paper strip with n numbers on it. Let's call them ai from left to right.

Now Alexandra wants to split it into some pieces (possibly 1). For each piece of strip, it must satisfy:

  * Each piece should contain at least l numbers.
  * The difference between the maximal and the minimal number on the piece should be at most s.



Please help Alexandra to find the minimal number of pieces meeting the condition above.

Input

The first line contains three space-separated integers n, s, l (1 ≤ n ≤ 105, 0 ≤ s ≤ 109, 1 ≤ l ≤ 105).

The second line contains n integers ai separated by spaces ( - 109 ≤ ai ≤ 109).

Output

Output the minimal number of strip pieces.

If there are no ways to split the strip, output -1.

Examples

Input

7 2 2
1 3 1 2 4 1 2


Output

3


Input

7 2 2
1 100 1 100 1 100 1


Output

-1

Note

For the first sample, we can split the strip into 3 pieces: [1, 3, 1], [2, 4], [1, 2].

For the second sample, we can't let 1 and 100 be on the same piece, so no solution exists.
// Don't place your source in a package


import javax.swing.*;
import java.lang.reflect.Array;
import java.text.DecimalFormat;
import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.*;
import java.util.stream.Stream;



// Please name your class Main
public class Main {
    static FastScanner fs=new FastScanner();
    static class FastScanner {
        BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st=new StringTokenizer("");
        public String next() {
            while (!st.hasMoreElements())
                try {
                    st=new StringTokenizer(br.readLine());
                } catch (IOException e) {
                    e.printStackTrace();
                }
            return st.nextToken();
        }
        int Int() {
            return Integer.parseInt(next());
        }

        long Long() {
            return Long.parseLong(next());
        }

        String Str(){
            return next();
        }
    }


    public static void main (String[] args) throws java.lang.Exception {
        PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
        //reading /writing file
        //Scanner sc=new Scanner(new File("input.txt"));
        //PrintWriter pr=new PrintWriter("output.txt");

        int T=1;
        for(int t=0;t<T;t++){
            int n=Int();
            int s=Int();
            int l=Int();
            int A[]=Arr(n);

            Solution sol=new Solution(out);
            sol.solution(A,l,s);
        }
        out.close();

    }

    public static int[] Arr(int n){
        int A[]=new int[n];
        for(int i=0;i<n;i++)A[i]=Int();
        return A;
    }
    public static int Int(){
        return fs.Int();
    }
    public static long Long(){
        return fs.Long();
    }
    public static String Str(){
        return fs.Str();
    }

}








class Solution {
    PrintWriter out;
    int INF = Integer.MAX_VALUE;
    int MOD = 1000000007;

    public Solution(PrintWriter out) {
        this.out = out;
    }



    public void solution(int A[],int k,int s) {
        int n =A.length;
        int dp[]=new int[n];
        Arrays.fill(dp,INF);
        LinkedList<int[]>mins=new LinkedList<>();
        LinkedList<int[]>maxs=new LinkedList<>();

        for(int i=0,j=0;i<A.length;i++){
            int cur=A[i];
            while(mins.size()>0&&cur<mins.getLast()[1])mins.removeLast();
            mins.addLast(new int[]{i,cur});
            while(maxs.size()>0&&cur>maxs.getLast()[1])maxs.removeLast();
            maxs.addLast(new int[]{i,cur});

            while(j<i){
                while(mins.size()>0&&mins.getFirst()[0]<j)mins.removeFirst();
                while(maxs.size()>0&&maxs.getFirst()[0]<j)maxs.removeFirst();
                int min=mins.getFirst()[1];
                int max=maxs.getFirst()[1];
                int dif=max-min;
                if(dif>s){
                    j++;
                }
                else{
                    if(get(dp,j-1)==INF){
                        j++;
                    }
                    else{
                        break;
                    }
                }
            }

            if(i-j+1>=k&&get(dp,j-1)!=INF){
                dp[i]=1+get(dp,j-1);
            }

            /*System.out.println(j+"  "+i);
            System.out.println(Arrays.toString(dp));
            System.out.println();*/
        }





        if(dp[A.length-1]==INF){
            out.println(-1);
        }
        else{
            out.println(dp[A.length-1]);
        }

    }

    public int get(int dp[],int i){
        if(i<0)return 0;
        return dp[i];
    }


}

















