#include <bits/stdc++.h>   using namespace std;   int main() {     int n;     cin >> n;     int *p = new int[n + 1], c = 0;     int *m = new int[n + 1];     for (int i = 0; i <= n; i++) {       p[i] = m[i] = 0;       c ^= i;       m[i] = c;     }     int f = 0;     for (int i = 1; i <= n; i++) {       cin >> p[i];       f ^= p[i];     }     int r = 0;     for (int i = 2; i <= n; i++) {       int grps = (n / i);       int rem = n % i;       if (grps & 1) r ^= m[i - 1];       r ^= m[rem];     }     cout << (r ^ f);     return 0;   }   