#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int INF = 1000000100;
const ll INFL = 2e18;
template <class T>bool chmin(T &a, T b){ if (a > b) { a = b; return true;} else return false;}
template <class T>bool chmax(T &a, T b){ if (a < b) { a = b; return true;} else return false;}

int main() {
    int N;
    cin >> N;

    int cnt[61] = {}; 
    for (int i = 0;i <= 60;i++) {
        cnt[i] = N;
    }

    for (int i = 0;i < N;i++) {
        int now = 0;
        ll A;
        cin >> A;
        while(A > 0) {
            if (A % 2 == 1)cnt[now]--;
            A /= 2;
            now++;
        }
    }

    for (int i = 0;i <= 60;i++) {
        if (cnt[i] == N) { 
            ll ans = 1LL << (ll)i;
            cout << ans << endl;
            return 0;
        }
    }

}