#include <bits/stdc++.h>   using namespace std;   int main() {     int t, j;     cin >> t;     for (j = 0; j <= t - 1; j++) {       int a, b, c, n;       cin >> a >> b >> n;       n = n % 3;       c = a ^ b;       if (n == 0) {         cout << a << endl;       } else if (n == 1) {         cout << b << endl;       } else {         cout << c << endl;       }     }   }   