#include <iostream>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <list>
#include <iterator>
#include <cassert>
#include <numeric>
#include <functional>
#include <ctime>
#include <bitset>
#pragma warning(disable:4996) 

//#define ATCODER
#ifdef ATCODER
#include <atcoder/all>
#endif

typedef long long ll;
typedef unsigned long long ull;
#define LINF  9223300000000000000
#define LINF2 1223300000000000000
#define LINF3 1000000000000
#define INF 2140000000
//const long long MOD = 1000000007;
const long long MOD = 998244353;

using namespace std;
#ifdef ATCODER
using namespace atcoder;
#endif

char str[3][400005];

void solve()
{
    int n, K;
    scanf("%d%d%s", &n, &K, str[0]);
    int num = n - K;
    int offs = (num-1) / 2;
    int id = (num % 2 == 0 ? 2 : 1);
    for (int k = 0; k < 2; k++) {
        for (int i = 0; i < n; i++) {
            str[k + 1][i] = '1';
            if (str[k][i] == '1' && str[k][i + 1] == '1') {
                str[k + 1][i] = '0';
            }
        }
    }
    vector<char> v;
    for (int i = offs; i < offs + K; i++) {
        v.push_back(str[id][i]);
    }
    v.push_back('\0');
    printf("%s\n", &v[0]);

    return;
}

int main()
{
#if 1
    solve();
#else
    int T, t;
    scanf("%d", &T);
    for (t = 0; t < T; t++) {
        //printf("Case #%d: ", t + 1);
        solve();
    }
#endif
    return 0;
}