#include <bits/stdc++.h>

using namespace std;
using ll = long long;

int main() {
    int k;
    cin >> k;
    vector<ll> nums;
    ll temp;
    for (int i = 0; i < k; i++) {
        cin >> temp;
        nums.push_back(temp);
    }

    ll a;
    ll out = nums[0];
    for (int i = 1; i < k; i++) {
        a = nums[i];
        for (int j = 0; j < 10000; j++) {
            if (((a>>j)&1) && ((out>>j)&1)) {out|=1<<(j+1); continue;}
            if (((a>>j)&1) || ((out>>j)&1)) {
                out|=1<<j;
            }

        }
    }
    cout << out << '\n';
    return 0;
}