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.*;

public class Problem implements Runnable {
    private void solve() throws IOException {
        int n=readInt(), m=readInt();
        String s=readToken();
        int[] count=new int[26];
        boolean ans=true;
        for (int i=0;i<n;i++) {
            count[s.charAt(i)-'a']++;
            if (count[s.charAt(i)-'a']>m) ans=false;
        }
        out.print(ans?"YES":"NO");
    }
    public static void main(String[] args) throws IOException {
        new Problem().run();
    }

    private void init() throws FileNotFoundException {
        Locale.setDefault(Locale.US);
        String fileName = "";
        if (fileName.isEmpty()) {
            in = new BufferedReader(new InputStreamReader(System.in));
            out = new PrintWriter(System.out);
        } else {
            in = new BufferedReader(new FileReader(fileName + ".in"));
            out = new PrintWriter(fileName + ".out");
        }
    }

    public void run() {
        try {
            init();
            solve();
            out.close();
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(-1);
        }
    }

    private static BufferedReader in;
    private static StringTokenizer tok;
    private static PrintWriter out;

    private static String readToken() throws IOException {
        while (tok == null || !tok.hasMoreTokens()) {
            tok = new StringTokenizer(in.readLine());
        }
        return tok.nextToken();
    }

    private static int readInt() throws IOException {
        return Integer.parseInt(readToken());
    }

    private static double readDouble() throws IOException {
        return Double.parseDouble(readToken());
    }

    private static long readLong() throws IOException {
        return Long.parseLong(readToken());
    }
}