#include <bits/stdc++.h>
using namespace std;
bool sortbysec(const pair<int, int> &a, const pair<int, int> &b) {
  return (a.second < b.second);
}
vector<pair<long long, long long> > v;
vector<long long> vv, v1, v2, v3;
vector<char> ch;
vector<string> str;
set<pair<int, int> > s;
int arr[1000000];
using namespace std;
int main() {
  int t, k;
  cin >> t >> k;
  string s;
  cin >> s;
  for (int i = 0; i < 26; i++) {
    arr[i] = 0;
  }
  for (int i = 0; i < s.length(); i++) {
    arr[s[i] - 'a']++;
  }
  for (int i = 0; i < 26; i++) {
    if (arr[i] == 0) {
      arr[i] = -1;
    }
  }
  int x = 0;
  char cat;
  for (int i = 0; i < 26; i++) {
    if (arr[i] > 0) {
      if (arr[i] <= k) {
        k -= arr[i];
        arr[i] = 0;
      } else {
        cat = 'a' + i;
        break;
      }
    }
  }
  for (int i = 0; i < s.length(); i++) {
    if (arr[s[i] - 'a'] == 0) {
      continue;
    } else if (arr[s[i] - 'a'] > 0) {
      if (k > 0 && s[i] <= cat) {
        k--;
      } else {
        cout << s[i];
      }
    }
  }
  return 0;
}
