#include <bits/stdc++.h>

using namespace std;


unsigned long long count_set_bits(vector<unsigned long long> & a, unsigned long long n){
    unsigned long long r = 0;
    for (const auto & i: a){
        r += (i & (1ull << n)) != 0;
    }
    return r;
}

template<typename T>
void print(vector<T> & a){
    for (const auto &i: a){
        cout << i << " ";
    }
    cout << "\n";
}

signed main(){
    unsigned long long n;
    cin >> n;
    vector<unsigned long long> a(n);
    for (unsigned long long i = 0; i < n; ++i){
        cin >> a[i];
    }
    vector<unsigned long long> dp(64);
    dp[0] = count_set_bits(a, 0);
    unsigned long long res = 0;
    if (dp[0]) res = 1;
    for (unsigned long long i = 1; i < 64; ++i){
        dp[i] = dp[i-1] / 2 + count_set_bits(a, i);
        //cout << i << " Count: " << count_set_bits(a, i) << "\n";
        res |= ((dp[i] ? 1ull : 0ull) << i);
    }
    //print(dp);
    cout << res << endl;
}