#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
void shift(int& x) {
  x = (x>>1)+((x&1)<<15);
}
int main() {
  int N, MAX = 1<<16;
  cin >> N;
  vector<int> A(N+1);
  for( int i = 1; i <= N; i++ ) {
    cin >> A[i];
  }
  if( N >= 16 ) {
    cout << MAX-1 << endl;
  }else {
    vector<vector<int>> dp(N+1, vector<int>(MAX));
    dp[0][0] = true;
    for( int i = 1; i <= N; i++ ) {
      for( int j = 0; j < MAX; j++ ) {
        for( int k = 0; k < 16; k++ ) {
          dp[i][j|A[i]] |= dp[i-1][j];
          shift(A[i]);
        }
      }
    }
    for( int j = MAX-1; j >= 0; j-- ) {
      if( dp[N][j] ) {
        cout << j << endl;
        break;
      }
    }
  }
}