【Codeforces Round #429 (Div. 2) A】Generous Kefa

:http://codeforces.com/contest/841/problem/A

模拟,贪心,每个朋友尽量地多给气球。

#include <bits/stdc++.h>
using namespace std;
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define LL long long
#define rep1(i,a,b) for (int i = a;i <= b;i++)
#define rep2(i,a,b) for (int i = a;i >= b;i--)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define ms(x,y) memset(x,y,sizeof x)
#define ri(x) scanf("%d",&x)
#define rl(x) scanf("%lld",&x)
#define rs(x) scanf("%s",x+1)
#define oi(x) printf("%d",x)
#define ol(x) printf("%lld",x)
#define oc putchar(' ')
#define os(x) printf(x)
#define all(x) x.begin(),x.end()
#define Open() freopen("F:\rush.txt","r",stdin)
#define Close() ios::sync_with_stdio(0)

typedef pair<int,int> pii;
typedef pair<LL,LL> pll;

const int dx[9] = {0,1,-1,0,0,-1,-1,1,1};
const int dy[9] = {0,0,0,-1,1,-1,1,-1,1};
const double pi = acos(-1.0);
const int N = 110;

char s[N];
int n,k,num[N];

int main(){
    //Open();
    //Close();
    ri(n),ri(k);
    rs(s);
    rep1(i,1,n){
        num[s[i]-'a'+1]++;
    }
    rep1(i,1,k){
        int cnt = 0;
        rep1(i,1,26)
            if (num[i]){
                cnt++;
                num[i]--;
            }
        n-=cnt;
    }
    if (n==0){
        puts("YES");
    }else{
        puts("NO");
    }
    return 0;
}