Problem: One day Kefa found n baloons. For convenience, we denote color of i-th baloon as si — lowercase letter of the Latin alphabet. Also Kefa has k friends. Friend will be upset, If he get two baloons of the same color. Kefa want to give out all baloons to his friends. Help Kefa to find out, can he give out all his baloons, such that no one of his friens will be upset — print «YES», if he can, and «NO», otherwise. Note, that Kefa's friend will not upset, if he doesn't get baloons at all.

Input

The first line contains two integers n and k (1 ≤ n, k ≤ 100) — the number of baloons and friends.

Next line contains string s — colors of baloons.

Output

Answer to the task — «YES» or «NO» in a single line.

You can choose the case (lower or upper) for each letter arbitrary.

Examples

Input

4 2
aabb


Output

YES


Input

6 3
aacaab


Output

NO

Note

In the first sample Kefa can give 1-st and 3-rd baloon to the first friend, and 2-nd and 4-th to the second.

In the second sample Kefa needs to give to all his friends baloons of color a, but one baloon will stay, thats why answer is «NO».

Solution (in JAVA):

Solution:
import java.io.*;
import java.util.*;
import java.math.*;

public class utkarsh {

    InputStream is;
    PrintWriter out;
    
    long maxl = (long) 4e18, mod = (long)1e9 + 7L;
    int p[], s[], maxi = (int) 2e9, sz, np = 15485900, modi = (int)1e9 + 7;
    boolean b[];    // = isPrime();
    
    void solve(){
        //sz=sieve(); //sz = 1000001;
        //out.println(sz);
        //Enter code here utkarsh
        int i, n, k;
        n = ni();
        k = ni();
        int a[] = new int[26];
        char[] c = ns(n);
        for(i = 0; i < n; i++){
            a[c[i] - 'a']++;
        }
        for(i = 0; i < 26; i++){
            if(a[i] > k){
                out.println("NO");
                return;
            }
        }
        out.println("YES");
    }
    
    int sieve(){
        int i, j, n = np; 
        b = new boolean[n]; 
        s = new int[n];
        for(i = 3; i < n; i += 2) {
            b[i] = true;
            s[i-1] = 2;
        }
        b[2] = true;
        s[1] = 1;   //(UD)
        for(i = 3; i * i <= n; i += 2) {
            if ( b[i] ) {
                s[i] = i;
                for(j = i * i; j < n; j += i) {
                    b[j] = false;
                    if(s[j] == 0)   s[j] = i;
                }
            } 
        } 
	for( ; i < n; i++)  if(s[i] == 0)   s[i] = i;
        p = new int[n];
        p[0] = 2;
        j = 1; 
        for(i = 3; i < n; i += 2) {
            if ( b[i] ) {
                p[j++] = i; 
            }
        } 
        p = Arrays.copyOf(p, j);
        return j;
    }
    long modpow(long base, long exp, long modulus) { base %= modulus; long result = 1L; while (exp > 0) { if ((exp & 1)==1) result = (result * base) % modulus; base = (base * base) % modulus; exp >>= 1; } return result;
    }
    
    public static void main(String[] args) { new utkarsh().run();
    }
    void run(){ is = System.in; out = new PrintWriter(System.out); solve(); out.flush();
    }
    
    byte input[] = new byte[1024];
    int len = 0, ptr = 0;
    
    int readByte(){ if(ptr >= len){ ptr = 0; try{ len = is.read(input); }catch(IOException e){ throw new InputMismatchException(); } if(len <= 0){ return -1; } } return input[ptr++];
    }
    boolean isSpaceChar(int c){ return !( c >= 33 && c <= 126 ); 
    }
    int skip(){ int b = readByte(); while(b != -1 && isSpaceChar(b)){ b = readByte(); } return b;
    }
    
    char nc(){ return (char)skip();
    }
    String ns(){ int b = skip(); StringBuilder sb = new StringBuilder(); while(!isSpaceChar(b)){ sb.appendCodePoint(b); b=readByte(); } return sb.toString();
    }
    int ni(){ int n = 0,b = readByte(); boolean minus = false; while(b != -1 && !( (b >= '0' && b <= '9') || b == '-')){ b = readByte(); } if(b == '-'){ minus = true; b = readByte(); } if(b == -1){ return -1; } while(b >= '0' && b <= '9'){ n = n * 10 + (b - '0'); b = readByte(); } return minus ? -n : n;
    }
    long nl(){ long n = 0L; int b = readByte(); boolean minus = false; while(b != -1 && !( (b >= '0' && b <= '9') || b == '-')){ b = readByte(); } if(b == '-'){ minus = true; b = readByte(); } while(b >= '0' && b <= '9'){ n = n * 10 + (b - '0'); b = readByte(); } return minus ? -n : n;
    }
    double nd(){ return Double.parseDouble(ns());
    }
    float nf(){ return Float.parseFloat(ns());
    }
    int[] na(int n){ int a[] = new int[n]; for(int i = 0; i < n; i++){ a[i] = ni(); } return a;
    }
    char[] ns(int n){ char c[] = new char[n]; int i,b = skip(); for(i = 0; i < n; i++){ if(isSpaceChar(b)){ break; } c[i] = (char)b; b = readByte(); } return i == n ? c : Arrays.copyOf(c,i);
    }
}