#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define rep(i,n) for(int i=0; i<(int)(n); i++)
#define MOD int(1e9)+7
#define MOD2 int(998244353)
#define INF int(1e9)+7
#define LINF ll(1e18)+7
#define PI acos(-1)
#define P pair<ll,ll>
template <typename T>
inline bool chmax(T &a, const T &b){
  if(a<b) {a=b; return true;}
  else return false;
}
template <typename T>
inline bool chmin(T &a, const T &b){
  if(a>b) {a=b; return true;}
  else return false;
}
//Graph
struct Edge{
  int to; ll cost;
  Edge(int _to, ll _cost) : to(_to), cost(_cost) {}
};
typedef vector<Edge> Edges;
typedef vector<Edges> Graph;
void add_edge(Graph &g,int from,int to,ll cost,bool rev,ll rev_cost){
  g[from].push_back(Edge(to,cost));
  if(rev) g[to].push_back(Edge(from,rev_cost));
}

int n;
ll a[110];

void solve(){
  cin>>n;
  rep(i,n) cin>>a[i];
  rep(i,63){
    bool f=1;
    rep(j,n){
      if(a[j]>>i&1) f=0;
    }
    if(f){
      ll ans=(1LL<<i);
      cout<<ans<<endl;
      return;
    }
  } 
}

int main(){
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout<<setprecision(10)<<fixed;
  solve();
  return 0;
}