#include <bits/stdc++.h>   using namespace std;   void solve() {     long long int n, k;     cin >> n >> k;     string s;     cin >> s;     if (k == 0) {       cout << s;       return;     }     if (n == 1)       cout <<  0 ;     else {       if (s[0] >  1 ) {         s[0] =  1 ;         k--;       }       for (long long int i = 1; i < n && k > 0; i++) {         if (s[i] >  0 ) {           s[i] =  0 ;           k--;         }       }       cout << s;     }   }   signed main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     long long int t;     t = 1;     while (t--) {       solve();       cout <<   n ;     }     return 0;   }   