#include <bits/stdc++.h>
using namespace std;

using ll = long long;
using vi = vector<int>;
using vvi = vector<vector<int>>;
using pii = pair<int,int>;
using vll = vector<ll>;
using str = string;
using vstr = vector<string>;

#define PB push_back
#define ALL(x) (x).begin() (x).end()
#define FOR(i,s,f) for(int (i) = (s); i < (f); i++)

#define int long long
main(){
    
    int n;
    cin >>n;
    vvi mp(n);
    FOR(i,0,n){
        int x; cin >>x;
        int t = 1;
        FOR(j,0,18){
            int a = (x & t);
            if(a!= 0) mp[i].PB(1);
            else mp[i].PB(0);
            t*= 2;
        }

    }
    vi cisla(n,0);
    ll suma = 0;
    vi ans;
    int ct = 0;
    int kont = 1;
    FOR(i,0,18){
        FOR(j,0,n){
            //cisla[j]*=2;
            if(mp[j][i]){
                suma+=kont;
            }
            
        }
        if(suma >= kont){
            ans.PB(1);
        } else{
            ans.PB(0);
        }
        kont *=2;
    }
    kont = 1;
    ll odp = 0;
    FOR(i,0,18){
        odp += ans[i] * pow(2,i);
    }
    cout <<odp<<'\n';
}