#include <bits/stdc++.h>
using namespace std;
const int INF = 0x3f3f3f3f;
const int MOD = 100003;
const double EPSILON = 1e-10;
const int NMAX = 2e5 + 5;
const int MMAX = 4e5 + 5;
char x[NMAX];
int n, k;
int main() {
  ios::sync_with_stdio(0);
  cin.tie(NULL);
  cout.tie(NULL);
  cin >> n >> k;
  cin.get();
  cin.getline(x, 2e5 + 2);
  if (n == 1) {
    if (k == 0)
      cout << x;
    else
      cout << 0;
    return 0;
  }
  if (k > 0 && x[0] != '1') {
    x[0] = '1';
    --k;
  }
  int i = 1;
  while (k && i < n) {
    if (x[i] != '0') {
      x[i] = '0';
      --k;
    }
    ++i;
  }
  cout << x;
  return 0;
}
