// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
#define endl "\n"
#define pb push_back
#define int long long
#define fi first
#define se second
const int N = 3e5 + 5, M = 1e9 + 7, LG = 20;
int n , A[N] , x;
void solve(){
cin >> n;
map<int,int> mp;
vector<int> a;
for (int i=0 ; i<n ; i++){
cin >> x;
mp[x]++;
}
int ans = 0;
for (auto i : mp){
if(i.se&1) a.pb(i.fi);
if (i.se > 1){
ans ^= (2 * i.fi);
}
}
n = a.size();
for (int i=0 ; i<n ; i++){
for (int j=i ; j>=0 ; j--){
// cout << a[i]+a[j] << endl;
ans ^= (a[i] + a[j]);
}
}
cout << ans << endl;
}
signed main(){
// freopen("" , "r" , stdin);
// freopen("" , "w" , stdout);
// cout << setprecision(30);
ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
int ts = 1;
// cin >> ts;
while(ts--){
solve();
}
}
