#include <iostream>
#include <string>
#include <vector>
#include<algorithm>
#include <iomanip>
using namespace std;
typedef long long ll;
//定義場所//
ll i, j, k, l, m, n;
ll N;
////////////

int main()
{
	cin >> N;
	ll ans = 0;
	if (N == 1) {
		cout << 0;
	}
	else {
		for (i = N; i >= (N / 2) + 2; i--) {
			ans += i * ((N + 1 - i) + (N + 1 - i + 1));
		}
		if (N % 2 == 0) {
			ans += ((N / 2) + 1) * ((N / 2) + 1);
		}
		else {
			ans += ((N / 2) + 1);
		}
		cout << ans;
	}
}