#include <bits/stdc++.h>
const int inf = 0x3f3f3f3f;
const long long infll = 0x3f3f3f3f3f3f3f3f;
const long long mod = 1e9 + 7;
const double eps = 1e-7;
const double pi = acos(-1.0);
const int maxn = 2e5 + 500;
const int maxm = 4e5 + 5;
using namespace std;
char s[maxn];
int main() {
  ios::sync_with_stdio(false);
  int n, k;
  cin >> n >> k;
  cin >> s;
  if (k == 0)
    cout << s << endl;
  else {
    if (n == 1)
      cout << 0 << endl;
    else {
      if (s[0] != '1') {
        s[0] = '1';
        k--;
      }
      for (int i = 1; i < n && k > 0; i++) {
        if (s[i] == '0')
          continue;
        else {
          s[i] = '0';
          k--;
        }
      }
      cout << s << endl;
    }
  }
  return 0;
}
