//Author: Kevin
#include<bits/stdc++.h>
//#pragma GCC optimize("O2")
using namespace std;
#define ll long long
#define ull unsigned ll
#define pb emplace_back
#define mp make_pair
#define ALL(x) (x).begin(),(x).end()
#define rALL(x) (x).rbegin(),(x).rend()
#define srt(x) sort(ALL(x))
#define rev(x) reverse(ALL(x))
#define rsrt(x) sort(rALL(x))
#define sz(x) (int)(x.size())
#define inf 0x3f3f3f3f
#define pii pair<int,int>
#define lb(v,x) (int)(lower_bound(ALL(v),x)-v.begin())
#define ub(v,x) (int)(upper_bound(ALL(v),x)-v.begin())
#define uni(v) v.resize(unique(ALL(v))-v.begin())
#define longer __int128_t
void die(string S){puts(S.c_str());exit(0);}
int k,m;
vector<pii> G[(1<<12)];
int d[1<<12],c[1<<12];
bool check(string s)
{
	for(int i=0;i<m;i++)
		G[i].clear();
	for(int i=0;i<m;i++)
		for(int j=0;j<2;j++)
		{
			int nxt=((i<<1)|j)&(m-1);
			if(nxt<sz(s))
			{
				int w=j-(s[nxt]^48);
				G[i].pb(nxt,w);
				G[nxt].pb(i,-w);
			}
			else
			{
				G[i].pb(nxt+m,j);
				G[nxt+m].pb(i,-j);
			}
		}
	for(int i=sz(s);i<m;i++)
	{
		G[i+m].pb(i,0);
		G[i].pb(i+m,1);
	}
	memset(d,0x3f,sizeof(d));
	memset(c,0,sizeof(c));
	d[0]=0;
	deque<int> q;
	q.push_back(0);
	while(!q.empty())
	{
		int x=q.front();
		q.pop_front();
		for(auto pr:G[x])
		{
			int y=pr.first;
			int w=pr.second;
			if(d[y]>d[x]+w)
			{
				d[y]=d[x]+w;
				c[y]=c[x]+1;
				if(c[y]>m+m-sz(s)) return false;
				if(!sz(q)||d[y]>d[q.front()])
					q.push_back(y);
				else
					q.push_front(y);
			}
		}
	}
	return true;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	cout.tie(0);
	int t=1;
	while(t--)
	{
		cin>>k;
		m=(1<<(k+k+1));
		string s;
		cin>>s;
		if(check(s))
			cout<<s<<endl;
		else
		{
			int p=-1;
			for(int i=m-1;i>=0;i--)
				if(s[i]=='0')
					if(check(s.substr(0,i)+"1"))
					{
						p=i;
						break;
					}
			if(p==-1)
			{
				cout<<"no"<<endl;
				continue;
			}
			string ans=s.substr(0,p)+"1";
			for(int i=p+1;i<m;i++)
			{
				ans+="0";
				if(!check(ans))
					ans[i]='1';
			}
			cout<<ans<<endl;
		}
	}
	return 0;
}