#include <bits/stdc++.h>
using namespace std;

int main() {
  iostream::sync_with_stdio(0), cin.tie(0), cout.tie(0);

  int n;
  cin >> n;
  vector<int> A(n);
  for (int i = 0; i < n; i++) {
    cin >> A[i];
  }
  if (n > 15) {
    cout << (1 << 16) - 1 << '\n';
    return 0;
  }
  vector dp(n + 1, vector<int>(1 << 16));
  dp[0][0] = 1;
  for (int i = 0; i < n; i++) {
    set<int> seen;
    int x = A[i];
    while (!seen.count(x)) {
      seen.insert(x);
      x = x / 2 + ((x % 2) << 15);
    }
    for (int mask = 0; mask < (1 << 16); mask++) {
      if (dp[i][mask]) {
        dp[i + 1][mask] = 1;
        for (int a : seen) {
          dp[i + 1][mask | a] = 1;
        }
      }
    }
  }
  int ans = 0;
  for (int mask = 0; mask < (1 << 16); mask++) {
    if (dp[n][mask]) {
      ans = max(ans, mask);
    }
  }
  cout << ans << '\n';

  return 0;
}