#include <bits/stdc++.h>
#include <bitset>
using namespace std;
using ull = unsigned long long;

int main() {
    ull n;
    cin >> n;

    vector<ull> sumofbits(64);
    for (ull i = 0; i < n; ++i)
    {
        ull a;
        cin >> a;
        bitset<64> b(a);
        for (int i = 0; i < 64; ++i) {
            if (b[i] == 1)
            {
                sumofbits[i]++;
            }
        }
    }
    bitset<64> out(0);
    ull carry = 0;
    for (int i = 0; i < 64; ++i)
    {
        ull bits = sumofbits[i] + carry;
        if (bits> 0)
        {
            out[i] = 1;
        }
        carry = bits / 2;
    }
    cout << out.to_ullong() << endl;
    return 0;
}