#include <iostream>
#include <string>
#include <utility>
#include <algorithm>
#include <map>
#include <set>
#include <vector>
#include <cmath>
#include <cstdlib>
#include <queue>
#include <stack>
#include <iomanip>

using namespace std;

#define REP(i, n) for(ll i = 0;i < n;i++)
#define REPR(i, n) for(ll i = n;i >= 0;i--)
#define FOR(i, m, n) for(ll i = m;i < n;i++)
#define FORR(i, m, n) for(ll i = m;i >= n;i--)
#define REPO(i, n) for(ll i = 1;i <= n;i++)
#define ll long long
#define INF (ll)1 << 60
#define MINF (-1 * INF)
#define ALL(n) n.begin(),n.end()
#define MOD (ll)1000000007
#define P pair<ll, ll>


ll n, ans;
vector<ll> s;
int main() {
	cin >> n;
	if (n == 1) {
		cout << 0 << endl;
		return 0;
	}
	if (n % 2 == 1) {
		s.push_back(n);
		for (int i = 2; i < n; i += 2) {
			s.push_back(i);
			s.push_back(n - i);
		}
		s.push_back(n);
	}
	else {
		s.push_back(n);
		for (int i = 2; i <= n / 2; i += 2) {
			s.push_back(i);
			if (i != n - i)s.push_back(n - i);
		}
		for (int i = n / 2 + 1 - (n / 2) % 2; i < n; i += 2) {
			s.push_back(i);
			if (i != n - i)s.push_back(n - i);
		}
		s.push_back(n);
	}
	REP(i, s.size()) {
		//cout << s[i] << " ";
	}
	//cout << endl;
	REP(i, s.size() - 1) {
		ans += (s[i] * s[i + 1]) + s[i + 1] - s[i];
	}
	cout << ans << endl;
}