#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const ll MOD = 1000000007;
using P = pair<int,int>;
#define rep(i, n) for(int i = 0; i < n; i++)
#define all(x) (x).begin(),(x).end()

int main(){
    int n;
    cin >> n;
    vector<bool> ok(70,true);
    rep(i,n){
        ll a;
        int j = 0;
        cin >> a;
        while(a){
            if(a%2) ok[j] = false;
            a /= 2;
            j++;
        }
    }
    rep(i,70){
        if(ok[i]){
            cout << (ll)pow(2,i) << endl;
            return 0;
        }
    }
    
}