#include "iostream"
#include "climits"
#include "list"
#include "queue"
#include "stack"
#include "set"
#include "functional"
#include "algorithm"
#include "string"
#include "map"
#include "unordered_map"
#include "unordered_set"
#include "iomanip"
#include "cmath"
#include "random"
#include "bitset"
#include "cstdio"
#include "numeric"
#include "cassert"
#include "ctime"

using namespace std;

//constexpr long long int MOD = 1000000007;
constexpr long long int MOD = 998244353;
constexpr double EPS = 1e-8;

//int N, M, K, T, H, W, L, R;
long long int N, M, K, T, H, W, L, R;


int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	cin >> N >> K;
	string s;
	cin >> s;
	K = N - K;
	if (K > 1) {
		string t;
		for (int i = 0; i < N; i++) {
			bool ok = false;
			if (i && s[i - 1] == '1')ok = true;
			if (i + 1 < N && s[i + 1] == '1')ok = true;
			if (!ok)s[i] = '0';
		}
		for (int i = K / 2; i + K / 2 < N; i++) {
			t.push_back(s[i]);
		}
		s = t;
		K %= 2;
	}
	N = s.size();
	if (K) {
		string t;
		for (int i = 1; i < N; i++) {
			if (s[i] == '1' && s[i - 1] == '1')t.push_back('0');
			else t.push_back('1');
		}
		s = t;
	}
	cout << s << endl;
}