#include<iostream>
#include<deque>
using namespace std;
int N,K;
int main()
{
	cin>>N>>K;
	deque<int>Q;
	{
		string S;
		cin>>S;
		for(char c:S)Q.push_back(c-'0');
	}
	if(Q.size()>=K+2)
	{
		deque<int>nxt;
		for(int i=1;i+1<Q.size();i++)
		{
			if(Q[i]==0)nxt.push_back(0);
			else if(Q[i-1]==1||Q[i+1]==1)nxt.push_back(1);
			else nxt.push_back(0);
		}
		Q=nxt;
	}
	while(Q.size()>=K+2)
	{
		Q.pop_front();
		Q.pop_back();
	}
	if(Q.size()>K)
	{
		deque<int>nxt;
		for(int i=1;i<Q.size();i++)
		{
			if(Q[i-1]==1&&Q[i]==1)nxt.push_back(0);
			else nxt.push_back(1);
		}
		Q=nxt;
	}
	for(int i=0;i<K;i++)cout<<Q[i];
	cout<<endl;
}