#include <bits/stdc++.h>
using namespace std;
void print(vector<int> v) {
  for (long long int i = 0; i < v.size(); i++) {
    cout << v[i];
  }
}
int main() {
  long long int n, k;
  cin >> n >> k;
  string s;
  cin >> s;
  vector<int> v;
  for (long long int i = 0; i < s.length(); i++) {
    if (s[i] == '1') {
      v.push_back(1);
    }
    if (s[i] == '2') {
      v.push_back(2);
    }
    if (s[i] == '3') {
      v.push_back(3);
    }
    if (s[i] == '4') {
      v.push_back(4);
    }
    if (s[i] == '5') {
      v.push_back(5);
    }
    if (s[i] == '6') {
      v.push_back(6);
    }
    if (s[i] == '7') {
      v.push_back(7);
    }
    if (s[i] == '8') {
      v.push_back(8);
    }
    if (s[i] == '9') {
      v.push_back(9);
    }
    if (s[i] == '0') {
      v.push_back(0);
    }
  }
  if (v.size() == 1 && k > 0) {
    cout << 0;
    return 0;
  }
  int start = 0, pos = 0;
  while (start != k && pos < v.size()) {
    if (pos == 0 && v[pos] != 1) {
      v[pos] = 1;
      start++;
    } else if (pos != 0 && v[pos] != 0) {
      v[pos] = 0;
      start++;
    }
    pos++;
  }
  print(v);
  return 0;
}
