#include<bits/stdc++.h>
using namespace std;
#define N 100005
#define BOOST() {ios_base::sync_with_stdio(false);cin.tie(NULL);}
typedef long long int ll;
int main()
{
 	BOOST();
	ll n;
	cin>>n;
	ll tmp = n*(n+1)/2;
	ll minus = tmp - n;
//	cout<<tmp<<"\n";
	ll ans = tmp*tmp - (minus *minus);
	
	
	cout<<ans;
}