#include <bits/stdc++.h>
//eolibraries
#define lnf 3999999999999999999
#define inf 999999999
#define fi first
#define se second
#define pb push_back
#define all(c) (c).begin(),(c).end()
#define sz(c) (int)(c).size()
#define make_unique(a) sort(all(a)),a.erase(unique(all(a)),a.end());
#define rep(i,n) for(int i=0;i<n;i++)
#define drep(i,n) for(int i=n-1;i>=0;i--)
#define crep(i,x,n) for(int i=x;i<n;i++)
#define vec(...) vector<__VA_ARGS__>
#define _3E0svGb ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0)
//eodefine
using namespace std;
typedef long long ll;
typedef long double ld;
using pii=pair<int,int>;
using tpii=pair<pii,int>;
using vi=vec(int);
const int mxn=12000;

int main(){
_3E0svGb;
	int n;
	cin>>n;
	vec(ll) a(n);
	rep(i,n){
		cin>>a[i];
	}
	rep(j,64){
		bool pokita=1;
		rep(i,n){
			if(a[i]&(1LL<<j)) pokita=0;
		}
		if(pokita){
			cout<<(1LL<<j)<<"\n";
			break;
		}
	}
//	
	return 0;
}