#include <bits/stdc++.h>
using namespace std;
mt19937 rnd;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  if (n == 1) {
    if (k == 1) {
      cout << '0';
    } else
      cout << s;
    return 0;
  }
  if (s[0] != '1' && k > 0) {
    s[0] = '1';
    k--;
  }
  for (int i = 1; i < s.size(); i++) {
    if (s[i] == '0') continue;
    if (k == 0) break;
    s[i] = '0';
    k--;
  }
  cout << s;
  return 0;
}
