#include <bits/stdc++.h>
using namespace std;
int32_t main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  long long n, k;
  cin >> n >> k;
  if (k == n) {
    return 0;
  }
  long long r = k;
  string s;
  cin >> s;
  long long hash[26] = {0};
  for (long long i = 0; i < n; i++) {
    hash[s[i] - 'a']++;
  }
  for (long long i = 0; i < 26 && k > 0; i++) {
  ab:
    if (hash[i] > 0) {
      k--;
      hash[i]--;
      if (k > 0) {
        goto ab;
      } else {
        goto cd;
      }
    }
  }
cd:
  long long j = 0;
  char str[n];
  for (long long i = n - 1; i >= 0; i--) {
    if (hash[s[i] - 'a'] > 0) {
      hash[s[i] - 'a']--;
      str[j] = s[i];
      j++;
    }
  }
  for (long long i = n - r - 1; i >= 0; i--) cout << str[i];
  cout << "\n";
  return 0;
}
