#include <bits/stdc++.h>

using namespace std;

struct Edge {
    int v, w;
    Edge(int v, int w) : v(v), w(w) {}
};

const int N = 150, M = N * N;
int w, dis[N], cnt[N], vis[N], q[M];
string s, ans;
vector<Edge> G[N];

bool spfa() {
    memset(dis, 0x3f, sizeof(dis));
    memset(cnt, 0, sizeof(cnt));
    memset(vis, 0, sizeof(vis));
    int l = 0, r = -1;
    dis[0] = 0, vis[0] = true, q[++r] = 0;
    while (l <= r) {
        int u = q[l++];
        vis[u] = false;
        for (const Edge& e : G[u]) {
            if (dis[e.v] > dis[u] + e.w) {
                dis[e.v] = dis[u] + e.w;
                cnt[e.v] = cnt[u] + 1;
                if (cnt[e.v] > (1 << (w + w + 1)) + 3) return false;
                if (!vis[e.v]) q[++r] = e.v, vis[e.v] = true;
            }
        }
    }
    return true;
}

#define bin(x) bitset<16>(x).to_string().c_str()

#define shift(x, y) ((x) << 1 & ((1 << (w + w + 1)) - 1) | ((y) & 1))

bool check() {
    for (int i = 0; i < N; i++) G[i].clear();
    for (int i = 0; i < (1 << (w + w + 1)); i++) {
        int u = shift(i, 0), v = shift(i, 1);
        int top_b = i >> (w + w) & 1;
        G[u].emplace_back(v, 0);
        G[v].emplace_back(u, 0);
        int l = 0, r = 1;
        if (i < ans.size()) {
            if (ans[i] == '0') r = 0;
            else l = 1;
        }
        G[i].emplace_back(u, top_b - l);
        G[u].emplace_back(i, r - top_b);
    }
    return spfa();
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    cin >> w >> s;
    ans = s;
    if (check()) {
        cout << ans << endl;
        return 0;
    }
    for (int i = s.size() - 1; i >= 0; i--)
        if (s[i] == '0') {
            ans = s.substr(0, i);
            ans.push_back('1');
            if (check()) {
                while (ans.size() < s.size()) {
                    ans.push_back('0');
                    if (!check()) ans.back() = '1';
                }
                cout << ans << endl;
                return 0;
            }
        }
    cout << "no" << endl;
    return 0;
}