#include <bits/stdc++.h>
using namespace std;
const long long N = 2e6 + 7;
const long long mod = 1e9 + 7;
long long a, n, b, m, c, d, cnt, k;
long long mx, mx1, ans, sum, mn = 1e9;
vector<int> v, v1;
long long used[101];
string s, s1;
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n >> m;
  cin >> s;
  for (auto it : s) used[it - 'a']++;
  for (int i = 0; i < 26; i++) {
    if (m <= 0) break;
    cnt = m;
    m -= used[i];
    used[i] -= min(used[i], cnt);
  }
  for (int i = n - 1; i >= 0; i--) {
    if (used[s[i] - 'a'] > 0) s1 += s[i], used[s[i] - 'a']--;
  }
  reverse(s1.begin(), s1.end());
  cout << s1 << endl;
  return 0;
}
