#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
/*
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("-O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
*/
#define mp make_pair
#define ll long long
#define ld long double
#define pb push_back
#define fast_io ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define fs first
#define sc second
#define getfiles ifstream cin("input.txt"); ofstream cout("output.txt");
#define endl '\n'
#define pii pair<int, int>
const int INF = 2000000005;
const ll BIG_INF = 2000000000000000005;
const int mod = 1000000007;
const int P = 31;
const ld PI = 3.141592653589793238462643;
const double eps = 1e-9;
using namespace std;
using namespace __gnu_pbds;
bool valid(int x, int y, int n, int m) {
return x >= 0 && y >= 0 && x < n && y < m;
}
mt19937 rng(1999999973);
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
signed main() {
fast_io;
int ans = 0;
int n;
int a[10000];
cin >> n;
for (int i = 0; i < n; i++) {
cin >> a[i];
}
for (int i = 0; i < n; i++) {
for (int j = i; j < n; j++) {
ans ^= (a[i] + a[j]);
}
}
cout << ans;
return 0;
}
