Sicily 1200. Stick

// a ^ (b ^ b) ^ (c ^ c) ^ ... ^ (n ^ n) = a#include <iostream>using namespace std;int main(int argc, char **argv) {int n;while (cin >> n && n) {int res, tmp, nt = n - 1;cin >> res;while (nt--) {cin >> tmp;res ^= tmp;}cout << res << endl;}return 0;}