#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i = 0; i < (int)n; i++)
using ll = long long;

int shift(int x) {
  return x/2 + (1<<15)*(x % 2);
}

int main(){
  int n;
  cin >> n;
  vector<int> a(n);
  rep(i,n) cin >> a[i];
  int all = (1<<16)-1;
  if(n >= 16) {
    cout << all << endl;
    return 0;
  }
  vector<int> dp(1<<16);
  dp[0]++;
  rep(i,n) {
    vector<int> dpn(1<<16);
    rep(j,17) {
      a[i] = shift(a[i]);
      rep(x,1<<16) dpn[a[i]|x] += dp[x];
    }
    swap(dp,dpn);
  }
  int ans = 0;
  rep(i,1<<16) if(dp[i]) ans = max(ans,i);
  cout << ans << endl;
  return 0;
}