#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

template<typename T>
vector<vector<T>> vec2d(int n, int m, T v){
    return vector<vector<T>>(n, vector<T>(m, v));
}

template<typename T>
vector<vector<vector<T>>> vec3d(int n, int m, int k, T v){
    return vector<vector<vector<T>>>(n, vector<vector<T>>(m, vector<T>(k, v)));
}

template<typename T>
void print_vector(vector<T> v, char delimiter=' '){
    if(v.empty()) {
        cout << endl;
        return;
    }
    for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter;
    cout << v.back() << endl;
}

using P = pair<int, int>;

vector<P> run_length(string s){
    int pre = s[0]-'0';
    int cnt = 1;
    int n = s.size();
    vector<P> ans;
    for(int i = 1; i < n; i++){
        int x = s[i]-'0';
        if(x == pre){
            cnt++;
        }else{
            ans.push_back(P(pre, cnt));
            cnt = 1;
            pre = x;
        }
    }
    ans.push_back(P(pre, cnt));
    return ans;
}

vector<int> f(vector<int> v){
    int n = v.size();
    vector<int> u(n-1);
    for(int i = 0; i < n-1; i++){
        if(v[i] == 1 && v[i+1] == 1) u[i] = 0;
        else u[i] = 1;
    }
    return u;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    int n, k; cin >> n >> k;
    string s; cin >> s;
    vector<int> v(n);
    for(int i = 0; i < n; i++) v[i] = s[i]-'0';
    auto u = f(v);
    if(u.size()%2 != k%2){
        u = f(u);
    }
    int sz = u.size();
    int l = (sz-k)/2;
    for(int i = l; i < l+k; i++) cout << u[i];
    cout << endl;
}