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

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);

    int N; cin >> N;
    if(N >= 16) {
        cout << (1 << 16) - 1 << endl;
    } else {
        vector<int> A(N);
        rep(i,N) cin >> A[i];
        int LIM = (1 << 16);
        vector<vector<int>> dp(N + 1, vector<int>(LIM, 0));
        dp[0][0] = 1;
        rep(i,N) {
            rep(x,LIM) {
                rep(_,15) {
                    dp[i + 1][x | A[i]] |= dp[i][x];
                    A[i] = (A[i] / 2) + (1 << 15) * (A[i] % 2);
                }
            }
        }
        int ans = 0;
        rep(x,LIM) if(dp[N][x]) ans = max(ans, x);
        cout << ans << endl;
    }
}