#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define ub upper_bound
#define lb lower_bound
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define NeedForSpeed ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<ll> vll;
typedef vector<int> vii;
typedef vector<pll> vpll;
typedef vector<pii> vpii;
template<class T> bool umin(T& a, const T& b) {return a > b? a = b, true:false;}
template<class T> bool umax(T& a, const T& b) {return a < b? a = b, true:false;}
int msb(int val){return sizeof(int)*8-__builtin_clzll(val)-1;}
const int N = 2e6+5;
const int mod = 1e9+7;
const ll inf = 1e18;
const ld Pi = acos(-1);
#define MULTI 0
int n, m, s, k, ans, a[N];
void solve(int t_case){
cin>>n;
for(int i=0;i<n;i++) cin>>a[i];
ll res = 0;
for(int i=0;i<n;i++){
for(int j=i;j<n;j++){
res ^= (a[i] + a[j]);
}
}cout<<res<<"\n";
}
signed main(){
NeedForSpeed
if(!MULTI){
solve(1);
} else{
int t;
cin>>t;
for(int t_case = 1; t_case <= t; t_case++) solve(t_case);
}
return 0;
}
