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.util.*;
import java.io.*;
import java.math.*;
public class Main
{  
    static int MOD = (int)(1e9 + 7);
    public static void process()throws IOException
    {
     int n=ni();
     int k=ni();
     String s=nn();
     int freq[]=new int[26];
     s=s.toLowerCase();
     for(int i=0;i<n;i++)
        freq[s.charAt(i)-'a']++;
   int flag=0;
    for(int i=0;i<26;i++)
       {
        if(freq[i]>k)
            {flag=1;break;}
       } 
     if(flag==1)
        pn("NO");
    else
        pn("YES");

    }
    
    static AnotherReader sc;
    static PrintWriter out;
    public static void main(String[]args)throws IOException
    {
        out = new PrintWriter(System.out);
        sc=new AnotherReader();
        boolean oj = true;
 
        //oj = System.getProperty("ONLINE_JUDGE") != null;
        //if(!oj) sc=new AnotherReader(100);
 
        long s = System.currentTimeMillis();
      //int T=ni(); while(T-->0)
            process();
        out.flush();
        if(!oj)
            System.out.println(System.currentTimeMillis()-s+"ms");
        System.out.close();  
    }
    static void sort(long arr[],int n)
    {
    shuffle(arr,n);
    Arrays.sort(arr);
    }
    static void shuffle(long arr[],int n)
    {
        Random r=new Random();
        for(int i=0;i<n;i++)
        {
          long temp=arr[i];
          int pos=i+r.nextInt(n-i);
          arr[i]=arr[pos];
          arr[pos]=temp;
        }
    }
 
    static void pn(Object o){out.println(o);}
    static void p(Object o){out.print(o);}
    static void pni(Object o){out.println(o);System.out.flush();}
    static int ni()throws IOException{return sc.nextInt();}
    static long nl()throws IOException{return sc.nextLong();}
    static double nd()throws IOException{return sc.nextDouble();}
    static String nln()throws IOException{return sc.nextLine();}
    static String nn()throws IOException{return sc.next();}
    static long gcd(long a, long b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int gcd(int a, int b)throws IOException{return (b==0)?a:gcd(b,a%b);}
    static int bit(long n)throws IOException{return (n==0)?0:(1+bit(n&(n-1)));}
    static int[] iarr(int N)throws IOException{int[]ARR=new int[N];for(int i=0;i<N;i++){ARR[i]=ni();}return ARR;}
    static long[] larr(int N)throws IOException{long[]ARR=new long[N];for(int i=0;i<N;i++){ARR[i]=nl();}return ARR;}
    static boolean multipleTC=false;
 
/////////////////////////////////////////////////////////////////////////////////////////////////////////
    static class AnotherReader{BufferedReader br; StringTokenizer st;
    AnotherReader()throws FileNotFoundException{
    br=new BufferedReader(new InputStreamReader(System.in));}
    AnotherReader(int a)throws FileNotFoundException{
    br = new BufferedReader(new FileReader("input.txt"));}
    String next()throws IOException{
    while (st == null || !st.hasMoreElements()) {try{
    st = new StringTokenizer(br.readLine());}
    catch (IOException  e){ e.printStackTrace(); }}
    return st.nextToken(); } int nextInt() throws IOException{
    return Integer.parseInt(next());}
    long nextLong() throws IOException
    {return Long.parseLong(next());}
    double nextDouble()throws IOException { return Double.parseDouble(next()); }
    String nextLine() throws IOException{ String str = ""; try{
    str = br.readLine();} catch (IOException e){
    e.printStackTrace();} return str;}}
    
/////////////////////////////////////////////////////////////////////////////////////////////////////////////
}