#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using vi = vector<int>;
using vll = vector<ll>;
using namespace std;
int main()
{
    ios::sync_with_stdio(false); cin.tie(nullptr);
    ll n, len{};
    cin >> n;
    vi arr(50,0);
    
    for (ll it = 0; it < n; ++it) {
        ll i;
        cin >> i;
        ll j=0;
        while(i)
        {
            if(i & 1) arr[j]++;
            ++j;
            i >>= 1;
            len = max(len, j);
        }
    }

    ll sum = 0, carry = 0;
    for (int j = 0; j < len; ++j)
    {
        ll current = carry + arr[j];
        
        if (current) sum += pow(2, j);
        if (current >= 2) carry = current - 1;
    }
    while(carry)
    {
        sum += pow(2, len++);
        carry = carry / 2;
    }
    

    cout << sum << endl;
}