#include <iostream>
#include <algorithm>
#include <cmath>
#include <set>
#include <map>
#include <vector>
#include <string>
#include <sstream>
#include <cstring>
#pragma GCC optimize("inline")
#pragma GCC optimize("-fgcse,-fgcse-lm")
#pragma GCC optimize("-ftree-pre,-ftree-vrp")
#pragma GCC optimize("-ffast-math")
#pragma GCC optimize("-fipa-sra")
#pragma GCC optimize("-fpeephole2")
#pragma GCC optimize("-fsched-spec")
#pragma GCC optimize("Ofast,no-stack-protector")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
#define ll long long int
#define pb push_back
#define pf push_front
#define fi first
#define se second
#define all(x) x.begin(), x.end()
using namespace std;
ll ans, a[ 100111 ];
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
ll n;
cin >> n;
for(int i = 1; i <= n; i ++){
cin >> a[ i ];
}
for(int i = 1; i <= n; i ++){
for(int j = i; j <= n; j ++){
ans ^= (a[ i ] + a[ j ]);
}
}
cout << ans;
}
