#include <bits/stdc++.h>
using namespace std;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n, k; cin >> n >> k;
    string s; cin >> s;
    int eve = n - (n - k) / 2 * 2;
    string ans;
    if (eve == n) {
        ans = s;
    } else {
        for (int i = 0; i < eve; i++) {
            int ind = i + (n - eve) / 2;
            if (s[ind] == '1' && (s[ind - 1] == '1' || s[ind + 1] == '1')) {
                ans.push_back('1');
            } else {
                ans.push_back('0');
            }
        }
    }
    if (k != eve) {
        for (int i = 0; i < k; i++) {
            ans[i] = (ans[i] & ans[i + 1]) ^ 1;
        }
        ans.pop_back();
    }
    cout << ans;
}