G 100

/*

 ∧＿∧
( ･ω･｡)つ━☆・*。
⊂　 ノ 　　　・゜
しーＪ　　 Accepted

*/



// #pragma GCC optimize("O3")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define ll long long
#define all(x) begin(x), end(x)
#define x first
#define y second
#define int long long

using namespace std;
using namespace __gnu_pbds;

typedef long double ld;
template<typename T>
using kawaii_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

const ld PI = atan2(0, -1);

void seriy() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    cout << fixed << setprecision(14);
    #ifdef _offline
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif
}

const int MAXN = 1001;
const int MAXM = 600;
const int INF = 1e18 + 7;
const int BASE = 47;
const int MOD = 1e9 + 7;
const int MAXLOG = 51;
const ld EPS = 1e-6;

vector<int> a_int;
vector<bitset<MAXN>> a;
int n;
bitset<MAXN> b;

void add(bitset<MAXN> &s, int pw) {
    int p = pw;
    while(p < s.size() && s[p] == 1) {
        s[p] = 0;
        p++;
    }
    s[p] = 1;
}

void subtract(bitset<MAXN> &s, int pw) {
    int p = pw;
    while(p < s.size() && s[p] == 0) {
        s[p] = 1;
        p++;
    }
    s[p] = 0;
}

// bitset<MAXN> xor1(bitset<MAXN> &a, bitset<MAXN> &b) {
//     bitset<MAXN> ans;
//     for(int i = 0; i < max(a.size(), b.size()); i++) {
//         ans[i] = ((a[i] == b[i]) ? 0 : 1);
//     }
//     return ans;
// }

bitset<MAXN> ans;
bool flag = 0;

void solve(bitset<MAXN> cur, int pw, bitset<MAXN> cur_sum) {
    if(pw > b.size()) {
        bitset<MAXN> kek = cur_sum;
        if(kek == b) {
            flag = 1;
            ans = cur;
        }
        return;
    }
    // cerr << cur << " " << pw << " " << cur_sum << " " << b << '\n';
    bitset<MAXN> kek = cur_sum;
    if(cur_sum[pw] == b[pw] || kek == b) {
        solve(cur, pw + 1, cur_sum);
    }
    if(flag) {
        return;
    }
    bitset<MAXN> sum;
    for(int i = 0; i < n; i++) {
        add(a[i], pw);
        sum ^= a[i];
    }
    bitset<MAXN> sum_c = sum;
    // cerr << cur << " " << pw << " " << b << " " << sum_c << '\n';
    if((pw < b.size() && pw < sum_c.size() && sum_c[pw] == b[pw]) || sum_c == b) {
        cur[pw] = '1';
        solve(cur, pw + 1, sum);
    }
    for(int i = 0; i < n; i++) {
        subtract(a[i], pw);
    }
}

signed main() {
    seriy();
    int KEK = 1;
    while(KEK--) {
        cin >> n;
        a.resize(n);
        a_int.resize(n);
        int cur_sum_int = 0;
        bitset<MAXN> cur_sum;
        for(int i = 0; i < n; i++) {
            string h;
            cin >> h;
            reverse(all(h));
            for(int j = 0; j < h.size(); j++) {
                a[i][j] = ((h[j] == '1') ? 1 : 0);
            }
            cur_sum ^= a[i];
        }
        string bb;
        cin >> bb;
        reverse(all(bb));
        for(int i = 0; i < bb.size(); i++) {
            b[i] = ((bb[i] == '1') ? 1 : 0);
        }
        bitset<MAXN> s;
        solve(s, 0, cur_sum);
        string res = "";
        cerr << ans << '\n';
        res = ans.to_string();
        reverse(all(res));
        while(res.size() && res.back() == '0') {
            res.pop_back();
        }
        reverse(all(res));
        if(!res.size()) res = "0";
        if(!flag) {
            res = "-1";
        }
        cout << res;
    }
    return 0;
}