#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N=1e6+5;
signed main(){
	ios_base::sync_with_stdio(0);
	int n;
	cin>>n;
	int ans=0,i=2;
	while(i<=2*n){
		ans+=i*i;
		i+=2;
	}
	cout<<ans;
}