#include <bits/stdc++.h>
using namespace std;
int n, k;
string s;
int vist[400010];
void solve() {
  int i;
  memset(vist, 0, sizeof(vist));
  char ch = 'a';
  int flag;
  while (k) {
    flag = 0;
    while (1) {
      for (i = 0; i < n; i++) {
        if (!vist[i]) {
          if (s[i] == ch) {
            vist[i] = 1;
            flag = 1;
            k--;
            if (k == 0) return;
          }
        }
      }
      if (flag == 1)
        break;
      else
        ch++;
    }
  }
}
int main() {
  while (cin >> n >> k) {
    cin >> s;
    solve();
    for (int i = 0; i < n; i++)
      if (!vist[i]) cout << s[i];
    cout << endl;
  }
  return 0;
}
