//The Rumbling starts here:
//#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math")
//pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#define debug(n,m) cout<<"["<<#n<<"]->"<<n<<m
#include<bits/stdc++.h>
#define int long long
#define all(x) x.begin(),x.end()
#define pb push_back
using namespace std;
const int N=3e5+5;
const int mod=1e9+7;
const int inf=(1ll<<55)-1;
int a[N];
void levi() {
int n;
cin>>n;
for (int i=1;i<=n;i++) {
cin>>a[i];
}
int sum=0;
for (int i=1;i<=n;i++) {
for (int j=i;j<=n;j++) {
sum^=(a[i]+a[j]);
}
}
cout<<sum<<'\n';
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);int t=1;
#ifdef tests
cin>>t;
#endif
while(t--) levi();
}
