#include <bits/stdc++.h>
using namespace std;
#include <atcoder/all>
using namespace atcoder;
using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using pii = pair<int, int>;
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define repr(i, n) for (int i = (int)(n - 1); i >= 0; --i)

using bits = bitset<400000>;
int main() {
    int n, K;
    string s;
    cin >> n >> K >> s;
    bits ret(s);
    rep(i, n - K) {
        if (i & 1) {
            ret |= ret >> 1;
        } else {
            ret &= ret >> 1;
        }
    }
    if ((n - K) & 1) ret = ~ret;
    repr(i, K) cout << (ret.test(i) ? '1' : '0');
    cout << endl;
    return 0;
}