#include <iostream>
#include <bits/stdc++.h>

using namespace std;


int main()
{
    //string x = ""+bitset<80>{5}.to_string();

    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int n;
    unsigned long long x;
    cin >> n;

    vector<int> ones;
    for(int i = 0; i < 80; i++){
        ones.push_back(0);
    }
    for(int i = 0; i < n; i ++){

        cin >> x;
        string bin = bitset<80>{x}.to_string();
        for(int i = 0; i < bin.size(); i++){
            if(bin[i] == '1')ones[i]++;
        }

    }
    string res = "";
    if(ones[79] >= 1)res+='1';
    else res+='0';
    for(int i = 78; i >= 0; i--){
        ones[i] += ones[i+1]/2;
        if(ones[i] > 0){
            res = '1' + res;
        }
        else {
            res = '0' + res;
        }

        }
        unsigned long long ans= 0,exp = 1;
    for(int i = res.size()-1; i >= 0; i--){
        if(res[i] == '1') {
           ans += exp;
        }              //ans += pow(2, res.size() - i - 1);
        exp *= 2;
    }
    //cout << res << endl;
    cout << ans;

    return 0;
}