#include <bits/stdc++.h>
using namespace std;
int len, k;
void sw(string &str, int k) {
  string ss = str.substr(0, k + 1);
  reverse(ss.begin(), ss.end());
  for (int i = 0; i <= k; i++) str[i] = ss[i];
}
int main() {
  string str;
  scanf("%d", &len);
  scanf("%d", &k);
  cin >> str;
  map<char, int> make_pair;
  for (int i = 0; i < len; ++i) {
    make_pair[str[i]] += 1;
  }
  char lim;
  bool flag = true;
  int del = 0;
  long long int sum = 0;
  char i;
  for (i = 'a'; i <= 'z'; ++i) {
    sum += make_pair[i];
    if (sum == k) {
      lim = i;
      del = 0;
      break;
    }
    if (sum > k) {
      lim = i - 1;
      sum -= make_pair[i];
      del = k - sum;
      break;
    }
  }
  if (i > 'z' && sum <= k) {
    cout << "\n";
    return 0;
  }
  for (int i = 0; i < len; ++i) {
    if (str[i] >= 'a' && str[i] <= lim) str[i] = '?';
  }
  int p = 0;
  for (int i = 0; p < del && i < len; ++i) {
    if (str[i] == lim + 1) {
      str[i] = '?';
      ++p;
    }
  }
  for (int i = 0; i < len; ++i) {
    if (str[i] != '?') cout << str[i];
  }
  cout << "\n";
  return 0;
}
