#include <bits/stdc++.h>   using namespace std;   template <typename A, typename B, typename C>   struct triple {     A X;     B Y;     C Z;     triple(A a = 0, B b = 0, C c = 0) : X(a), Y(b), Z(c) {}   };   template <typename A, typename B, typename C>   triple<A, B, C> make_triple(A a = 0, B b = 0, C c = 0) {     return triple<A, B, C>(a, b, c);   }   template <typename A, typename B, typename C>   bool operator<(const triple<A, B, C>& a, const triple<A, B, C>& b) {     if (a.X != b.X) return a.X < b.X;     if (a.Y != b.Y) return a.Y < b.Y;     return a.Z < b.Z;   }   template <typename T, typename SS>   ostream& operator<<(ostream& ofs, const pair<T, SS>& p) {     ofs <<  (   << p.first <<   ,   << p.second <<   ) ;     return ofs;   }   template <typename T>   void print(T a) {     for (auto i : a) cout << i <<    ;     cout <<   n ;   }   template <typename T>   T max(T a, T b, T c) {     return max(a, max(b, c));   }   template <typename T>   T min(T a, T b, T c) {     return min(a, min(b, c));   }   struct custom_hash {     static uint64_t splitmix64(uint64_t x) {       x += 0x9e3779b97f4a7c15;       x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;       x = (x ^ (x >> 27)) * 0x94d049bb133111eb;       return x ^ (x >> 31);     }     size_t operator()(uint64_t x) const {       static const uint64_t FIXED_RANDOM =           chrono::steady_clock::now().time_since_epoch().count();       return splitmix64(x + FIXED_RANDOM);     }   };   signed main() {     srand(time(NULL));     cin.tie(0);     cout.tie(0);     ios_base::sync_with_stdio(false);     long long n;     cin >> n;     vector<long long> a(n);     for (long long i = 0; i < (n); i++) cin >> a[i];     long long ans = 0;     auto solve = [&](long long v) {       vector<long long> b(a);       long long pw = 1 << v;       for (long long i = 0; i < (n); i++) b[i] %= (pw * 2);       sort(b.begin(), b.end());       long long c = 0;       auto count = [&](long long l, long long r) -> long long {         return lower_bound(b.begin(), b.end(), r) -                lower_bound(b.begin(), b.end(), l);       };       for (long long i = 0; i < (n); i++)         c += (count(pw - b[i], pw * 2 - b[i]) +               count(pw * 3 - b[i], pw * 4 - b[i]));       for (long long i = 0; i < (n); i++)         if ((2 * b[i]) & pw) c--;       c >>= 1;       return c & 1;     };     for (long long i = 0; i < (25); i++)       if (solve(i)) ans += 1LL << i;     cout << ans <<   n ;   }   