#include <bits/stdc++.h>
using namespace std;
const int MAX = 1e3 + 5;
queue<int> pos[30];
int main() {
  int n, k;
  cin >> n >> k;
  char s[n + 5];
  cin >> s;
  if (n == k) return 0;
  for (int i = 0; i < n; i++) pos[s[i] - 'a'].push(i);
  int f = 0;
  for (int i = 0; i < k; i++) {
    while (pos[f].empty()) f++;
    s[pos[f].front()] = '*';
    pos[f].pop();
  }
  for (int i = 0; i < n; i++)
    if (s[i] != '*') printf("%c", s[i]);
  return 0;
}
