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

int64_t shift(int64_t x) { return x / 2 + (1ull << 15) * (x % 2); }

int main() {
    int64_t N;
    cin >> N;
    vector<int64_t> A(N);
    for (int64_t& a : A) {
        cin >> a;
    }

    const int64_t M = 16;
    const int64_t max_bit = (1ull << M);
    vector<bool> can_make(max_bit, false);
    can_make[0] = true;
    for (int64_t i = 0; i < N; i++) {
        vector<bool> new_can_make = can_make;
        for (int64_t k = 0; k < M; k++) {
            for (int64_t j = 0; j < max_bit; j++) {
                const int64_t nj = (j | A[i]);
                new_can_make[nj] = (new_can_make[nj] || can_make[j]);
            }

            A[i] = shift(A[i]);
        }

        can_make = new_can_make;
        if (can_make[max_bit - 1]) {
            cout << max_bit - 1 << endl;
            return 0;
        }
    }

    for (int64_t i = max_bit - 1; i >= 0; i--) {
        if (can_make[i]) {
            cout << i << endl;
            return 0;
        }
    }
}