#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>

using namespace std;
#define rep(i,n) for(int i=0;i<n;++i)
#define rep1(i,n) for(int i=1;i<=n;++i)
#define rrep(i,n) for(int i=n-1;i>=0;--i)
#define debug(output) if(debugFlag)cout<<#output<<"= "<<output<<"\n";
using lint = long long;
typedef pair<int,int> P;
const bool debugFlag=true;
const lint linf=1.1e18;const int inf=1.01e9;
constexpr int MOD=1000000007;
template<class T>bool chmax(T &a, const T &b) { if(a < b){ a = b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if(a > b){ a = b; return 1; } return 0; }

#define bitsize 400050

signed main(){
    int n,k;cin>>n>>k;
    string s;cin>>s;
    bitset<bitsize> dp;
    rep(i,n)if(s[i]=='1')dp[bitsize-1-i]=true;
    rep(_z,n-k){
        dp=~(dp&(dp<<1));
    }
    string res=dp.to_string();
    rep(i,k)cout<<res[i];
    cout<<"\n";
    return 0;
}