#include <bits/stdc++.h>

using namespace std;

using ll = long long;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    ll n; cin >> n;
    vector<ll> cnts(64, 0);
    for(ll i = 0; i < n; i++){
        ll a; cin >> a;
        for(ll b = 0; b < 64; b++) {
            if(a & (1 << b)) cnts[b]++;
        }
    }

    ll res = 0;
    for(ll b = 0; b < 64; b++){
        ll cnt = 1;
        bool p = 0;
        for(ll bb = b; bb >= 0; bb--) {
            cnt -= cnts[bb];
            if(cnt <= 0) {
                p = 1;
                break;
            }
            cnt *= 2;
        }
        if(p) {
            res |= (1 << b);
        }
    }
    cout << res << "\n";
}