#include <bits/stdc++.h>
#define int long long
using namespace std;
using vec_int = vector<int>;
using vec_ii = vector<vec_int>;
using vec_iii = vector<vec_ii>;
using vec_iiii = vector<vec_iii>;
using P = pair<int,int>;
using T = tuple<int,int,int, int>;
using ll = long long;
using ld = long double;
#define rep(i, n) for(int i = 0; i < (int)(n); i++)

void cout_line(vector<int> &a){
    for(int i=0;i<a.size();i++){
        if(i<a.size()-1){
            cout<<a.at(i)<<" ";
        }else{
            cout<<a.at(i)<<endl;
        }
    }
}

signed main(){
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    int N; cin>>N;
    vec_int A(N); rep(i,N)cin>>A.at(i);
    for(int i=0;i<62;i++){
        int flag = 1;
        for(int j=0;j<N;j++){
            if((A.at(j)>>i)%2==1){
                flag= 0;
                break;
            }
        }
        if(flag==0)continue;
        int ans = 1;
        cout<<(ans<<i)<<endl;
        return 0;
    }


    return 0;
}