A. Generous Kefa

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

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 2aabb

output

YES

input

6 3aacaab

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».

解题说明：此题确保每个人拿到的气球不一样颜色，首先统计各色气球个数，然后判断够不够分即可。

// codeforece.cpp: 定义控制台应用程序的入口点。//#include<cstdio>#include<iostream>#include<string>#include<cstring>using namespace std;int main(){int n, k, i, b[100], a[123] = { 0 }, j;char s[100], ch;scanf("%d%d", &n, &k);scanf("%s", s);for (i = 0; i<n; i++){ch = s[i];a[ch] = a[ch] + 1;}for (i = 97; i<123; i++){if (a[i]>k){printf("NO\n");exit(0);}}printf("YES\n");return 0;}