#include <iostream>
#include <vector>
#include <cmath>
#include <map>
#include <set>
#include <iomanip>
#include <queue>
#include <algorithm>
#include <numeric>
#include <deque>
#include <complex>
#include <cassert>

using namespace std;
using ll = long long;

int main(){

    ll N;
    cin >> N;
    vector<ll> A(N);
    for (int i=0; i<N; i++) cin >> A[i];
    bool f;
    for (int i=0; i<=62; i++){
        f=1;
        for (int j=0; j<N; j++){
            if (A[j] & 1LL<<i) f=0;
        }
        if (f){
            cout << (1LL<<i) << endl;
            break;
        }
    }

    return 0;
}