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

using ll = long long;
using ld = long double;
const ll mod = 998244353;
const ll INF = (1LL << 60);

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

int main() {
    int N;
    cin >> N;
    vector<int> A(N);
    for(int i = 0; i < N; i++) cin >> A[i];
    sort(A.rbegin(), A.rend());
    int ans = 0;
    for(int i = 0; i < N; i++) {
        int rev = ans;
        for(int cnt = 0; cnt <= 16; cnt++) {
            rev = max(rev, (ans | A[i]));
            A[i] = shift(A[i]);
        }
        ans = rev;
    }
    cout << ans << endl;
    return 0;
}