#include <bits/stdc++.h>   using namespace std;   priority_queue<int, vector<int>, less<int> > num;   int main() {     int n, x;     cin >> n;     for (int i = 1; i <= n; i++) {       cin >> x;       num.push(x);     }     cout << ((num.top()) xor (x)) <<   n ;   }   