#include<bits/stdc++.h>
#include <atcoder/all>
#ifdef LOCAL
#include <debug_print.hpp>
#define debug(...) debug_print::multi_print(#__VA_ARGS__, __VA_ARGS__)
#else
#define debug(...) (static_cast<void>(0))
#endif
using namespace atcoder;
using mint=modint998244353;
using namespace std;
using ll=long long;
using ul=unsigned long long;
int dx[8] = {-1, 1, 0, 0, -1, -1, 1, 1};
int dy[8] = {0, 0, -1, 1, -1, 1, -1, 1};
using Graph=vector<vector<int>>;

int main(){
    int N;
    cin>>N;
    vector<ll>A(N);
    for(int i=0;i<N;i++)cin>>A[i];
    for(int i=0;i<61;i++){
        bool ok=true;
        for(int j=0;j<N;j++){
            if((A[j]>>i)&1){ok=false;break;}
        }
        if(ok){
            cout<<(1ll<<i)<<endl;
            return 0;
        }
    }

}