/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2022.08.13 06:58:14
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;


int main() {
    int n,k;cin >> n >> k;
    k = n+1-k;
    string s;cin >> s;
    if (k == 1) {
        cout << s << endl;
        return 0;
    }
    for (int i = 1; i < n-1; i++) {
        if (s[i-1] == '0' && s[i+1] == '0') {
            s[i] = '0';
        }
    }
    if (k % 2 == 1) {
        for (int i = k/2; i < n-k/2; i++) {
            cout << s[i];
        }
        cout << endl;
    }
    else {
        string t;
        for (int i = 0; i < n-1; i++) {
            if (s[i]=='0'||s[i+1]=='0') t.push_back('1');
            else t.push_back('0');
        }
        cout << t.substr((k-1)/2,n+1-k) << endl;
    }
    return 0;
}