#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ull = unsigned long long;

ll MOD = 1'000'000'007;


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    cin >> n;
    vector<ull> a(n);
    vector<ull> pf(n);
    ull ans = 0;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        ans |= a[i];
    }
    pf[0] = a[0];
    for (int i = 1; i < n; i++) {
        pf[i] = pf[i - 1] + a[i];
        ans |= pf[i];
    }
    cout << ans;
}