#include <bits/stdc++.h>
using namespace std;
const int maxn = 4e5 + 10;
int n, m;
char a[maxn];
int main() {
  scanf("%d%d", &n, &m);
  scanf("%s", a + 1);
  int flag;
  char s = 'a';
  while (1) {
    flag = 0;
    for (int i = 1; i <= n; i++) {
      if (a[i] == s) {
        a[i] = '$';
        flag = 1;
        m--;
      }
      if (m == 0) {
        for (int i = 1; i <= n; i++) {
          if (a[i] != '$') printf("%c", a[i]);
        }
        return 0;
      }
    }
    if (flag == 0) s++;
  }
}
