#include <bits/stdc++.h>
using namespace std;
template <typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> a) {
  return o << a.first << ' ' << a.second;
}
template <typename A, typename B>
istream& operator>>(istream& o, pair<A, B>& a) {
  return o >> a.first >> a.second;
}
const int mod = 998244353, abc = 864197532, N = 200005, K = 111;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k;
  string s;
  cin >> n >> k >> s;
  vector<int> v[26];
  for (int i = 0; i < n; ++i) v[s[i] - 'a'].push_back(i);
  for (int i = 0; i < 26; ++i) {
    reverse(v[i].begin(), v[i].end());
    while (k && !v[i].empty()) {
      v[i].pop_back();
      k--;
    }
  }
  vector<pair<int, char>> ans;
  for (int i = 0; i < 26; ++i) {
    while (!v[i].empty()) ans.emplace_back(v[i].back(), i), v[i].pop_back();
  }
  sort(ans.begin(), ans.end());
  for (auto a : ans) cout << char(a.second + 'a');
}
