#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  int a[26] = {0};
  for (int i = 0; i < n; i++) {
    a[s[i] % 97]++;
  }
  string t = "";
  int count = 0;
  for (int i = 0; i < 26; i++) {
    if (a[i] > 0) {
      char ch = 97 + i;
      count = count + a[i];
      t = t + ch;
      if (count >= k) break;
    }
  }
  int l = t.length();
  int last = a[t[l - 1] % 97] - (count - k);
  for (int i = 0; i < l - 1; i++) {
    for (int j = 0; j < n; j++) {
      if (t[i] == s[j]) {
        s[j] = '0';
      }
    }
  }
  char ch = t[l - 1];
  int c = 0;
  for (int i = 0; i < n; i++) {
    if (s[i] == ch) {
      s[i] = '0';
      c++;
      if (c == last) break;
    }
  }
  for (int i = 0; i < n; i++) {
    if (s[i] != '0') cout << s[i];
  }
}
