/**
* In the name of Allah
* We are nothing and you're everything
* author: najmuddin
**/
#include <bits/stdc++.h>
#pragma GCC optimize("O3")
#pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("no-stack-protector")
#pragma GCC optimize("fast-math")
#pragma GCC optimize("trapv")
#pragma GCC optimize("inline")
using namespace std;
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
#define int ll
const char nl = '\n';
const int N = 1e8+5;
//const int inf = 1e18;
const int mod = 1e9+7;
void solve() {
int n; cin >> n;
vector<int> a(n);
for (auto &i: a)cin >> i;
if (n <= 4e3) {
int total = 0;
for (int i = 0; i < n; ++i) {
int x = a[i];
int xorsum = 0;
for (int j = i; j < n; ++j) {
xorsum ^= (a[j]+x);
if (i == 1 && j == 3)cout << xorsum;
}
total ^= xorsum;
}
cout << total;
return;
}
vector<int> v(4e3+10), c;
for (auto i: a) {
v[i] += 1;
if (v[i] == 1)c.push_back(i);
}
int total = 0;
for (int i = 0; i < sz(c); ++i) {
//if (v[c[i]] % 2 == 0) {
//continue;
//}
int x = c[i], xorsum = 0;
for (int j = i; j < sz(c); ++j) {
//ind2 += 1;
if (v[c[j]] % 2 == 0)continue;
xorsum ^= (c[j]+x);
}
total ^= xorsum;
}
for (auto i: c)
if (v[i]%2 == 0)total ^= (i+i);
cout << total;
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
//cin >> t;
while (t--) {
solve();
}
return 0;
}
