#include <bits/stdc++.h>

using namespace std;
using ll = long long;

void process() {
    ll n;
    cin >> n;
    vector<ll> a(n);
    for (ll i = 0; i < n; ++i) {
        cin >> a[i];
    }

    vector<ll> bits(60, 0);

    for (ll num : a) {
        for (ll i = 0; i < 60; ++i) {
            bool bit = ((num >> i) & 0b1) == 1;
            if (bit) ++bits[i];
        }
    }

    for (ll i = 0; i < 59; ++i) {
        ll got = bits[i];
        bits[i + 1] += (got / 2);
    }

    ll res = 0;
    for (ll i = 0; i < 60; ++i) {
        if (bits[i] >= 1) {
            res += (1 << i);
        }
    }

    cout << res << "\n";
}

int main() {
    std::ios::sync_with_stdio(false);
    process();
    cout.flush();
    return 0;
}