#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define sz size()
#define ff first
#define ss second
#define pb push_back
#define pii pair <int, int>
#define dur exit(0)
#define dur1 return(0)
const int N = 1e6 + 5;
const int BIT = 31;
int n, a[N];
int main () {
// freopen ("input.txt", "r", stdin);
ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
cin >> n;
for (int i = 1; i <= n; ++i) {
cin >> a[i];
}
int jogap = 0;
for (int i = 1; i <= n; ++i) {
for (int j = i; j <= n; ++j) {
int x = a[i] + a[j];
jogap ^= x;
}
}
cout << jogap;
}
