#include <bits/stdc++.h>
using namespace std;
bool b[500000];
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  cout.tie(nullptr);
  cerr.tie(nullptr);
  int n, k;
  string s;
  cin >> n >> k >> s;
  multiset<char> del;
  string t = s;
  sort(t.begin(), t.end());
  char x = 'a';
  for (int i = 0; i < k; ++i) {
    del.insert(t[i]);
    x = max(x, t[i]);
  }
  int num = del.count(x);
  for (int i = 0; i < n; ++i) {
    if (s[i] < x) {
      b[i] = 1;
    }
    if (s[i] == x && num > 0) {
      b[i] = 1;
      --num;
    }
  }
  string sol = "";
  for (int i = 0; i < n; ++i) {
    if (!b[i]) sol += s[i];
  }
  cout << sol << '\n';
}
