#include <iostream>
#include <vector>
#include <unordered_map>
#include <algorithm>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
int N;
cin >> N;
vector<int> V(N);
unordered_map<int, int> freq;
for (int i = 0; i < N; ++i) {
cin >> V[i];
freq[V[i]]++;
}
vector<int> S;
for (const auto& pair : freq) {
if (pair.second % 2 != 0) {
S.push_back(pair.first);
}
}
sort(S.begin(), S.end());
int result = 0;
int len_S = S.size();
for (int i = 0; i < len_S; ++i) {
int x = S[i];
int cnt = freq[x];
int pairs = cnt * (cnt + 1) / 2;
if (pairs % 2 == 1) {
result ^= (x + x);
}
for (int j = i + 1; j < len_S; ++j) {
int y = S[j];
result ^= (x + y);
}
}
cout << result << endl;
return 0;
}
