#include <bits/stdc++.h>
int main() {
  int x[2], y, t = 97;
  for (y = 0; y < 2; y++) {
    scanf("%d", &x[y]);
  }
  int count = 0;
  char list[x[0]];
  scanf("%s", list);
  while (count < x[1]) {
    for (y = 0; y < x[0]; y++) {
      if ((int)list[y] == t) {
        list[y] = '{';
        count++;
      }
      if (count == x[1]) {
        break;
      }
    }
    t++;
  }
  for (y = 0; y < x[0]; y++) {
    if (list[y] != '{') {
      printf("%c", list[y]);
    }
  }
}
