#include <bits/stdc++.h>
using namespace std;
char str[400010];
int cnt[30];
int arr[30];
int where[30][400010];
int main() {
  int n, k;
  scanf("%d%d%s", &n, &k, str);
  int idx = 0;
  for (int i = 0; str[i] != 0; i++) {
    idx = str[i] - 'a';
    ++cnt[idx];
    where[idx][arr[idx]] = i;
    arr[idx]++;
  }
  for (int i = 0; i < 30; i++) {
    arr[i] = 0;
  }
  for (int i = 0; i < k; i++) {
    for (int j = 0; j < 27; j++) {
      if (cnt[j] == 0) continue;
      idx = where[j][arr[j]];
      ++arr[j];
      --cnt[j];
      str[idx] = '.';
      break;
    }
  }
  for (int i = 0; str[i] != 0; i++) {
    if (str[i] != '.') printf("%c", str[i]);
  }
}
