#include <bits/stdc++.h>

#define all(x) begin(x), end(x)

using namespace std;
using i32 = int;
using i64 = long long;
using ld = long double;

template <typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b and (a = b, true);}

template <typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b and (a = b, true);}

const i64 supl = LONG_LONG_MAX / 2 - 100;
const i32 supi = INT_MAX / 2 - 100;

void main_() {
    i32 n; cin >> n;
    vector as(n, 0);
    for (auto& a : as) {
        cin >> a;
    }
    if (n >= 15) {
        cout << (1 << 16) - 1 << endl;
        exit(0);
    }
    vector dp(n + 1, vector((1 << 16), false));
    dp[0][0] = true;
    for (i32 i = 0 ; i < n ; i++) {
        for (i32 j = 0 ; j < (1 <<16) ; j++) {
            if (!dp[i][j]) {
                continue;
            }
            dp[i + 1][j] = true;
            for (i32 k = 0 ; k < 16 ; k++) {
                dp[i + 1][j | as[i]] = true; 
                as[i] = (as[i] / 2) + (1 << 15) * (as[i] % 2);
            }
        }
    }
    i32 ans = 0;
    for (i32 i = 0 ; i < (1 << 16) ; i++) {
        if (!dp.back()[i]) {
            continue;
        }
        ans = i;
    }
    cout << ans << endl;
}

int main() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    main_();

    return 0;
}