#include <bits/stdc++.h>
using namespace std;
string itosm(long long x) {
  if (x == 0) return "0";
  string res = "";
  while (x > 0) {
    res += ((x % 10) + '0');
    x /= 10;
  }
  reverse(res.begin(), res.end());
  return res;
}
long long stoim(string str) {
  long long res = 0;
  int p = 0;
  if (str[0] == '-') p++;
  for (int i = p; i < str.length(); i++) {
    res *= 10;
    res += (str[i] - '0');
  }
  return res;
}
const long long infll = 1e18 + 3;
const int inf = 1009000999;
const long double eps = 1e-7;
const int maxn = 1e6 + 1146;
const int baseint = 1000200013;
const long long basell = 1e18 + 3;
const long double PI = acos(-1.0);
const long long mod = 1e9 + 7;
long long binpow(long long x, long long st) {
  if (st == 0) return 1;
  if (st & 1) return binpow(x, st - 1) * x % mod;
  long long res = binpow(x, st >> 1);
  return res * res % mod;
}
int cnt[256];
void solve() {
  int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  for (char c : s) cnt[c - 'a']++;
  for (char c : s) {
    int sum = 0;
    for (int i = 0; i < c - 'a'; i++) sum += cnt[i];
    if (sum >= k)
      cout << c;
    else
      cnt[c - 'a']--, k--;
  }
}
int main() {
  srand(time(0));
  ios_base::sync_with_stdio(0);
  ;
  cin.tie(0);
  cout.tie(0);
  solve();
  return 0;
}
