#include <iostream>
#include <deque>
#include <vector>
#include <algorithm>
#include <utility>
#define llint long long

using namespace std;
typedef pair<llint, llint> P;

deque<llint> deq;
vector<P> vec;
vector<llint> vec2;
llint put[1000005];
llint n;

int main(void)
{
	cin >> n;
	if(n == 1){
		cout << 0 << endl;
		return 0;
	}
	
	for(int i = 1; i <= (n+1)/2; i++){
		if(i%2) deq.push_back(i);
		else deq.push_front(i);
	}
	
	for(int i = 0; i < (int)deq.size()-1; i++) vec.push_back(make_pair(deq[i]+deq[i+1], i));
	vec.push_back(make_pair(deq.back() + deq[0], (int)deq.size()-1));
	sort(vec.begin(), vec.end());
	
	int p = 0;
	for(int i = n; i >= (n+1)/2+1; i--){
		put[vec[p].second] = i;
		p++;
	}
	
	for(int i = 0; i < deq.size(); i++){
		vec2.push_back(deq[i]);
		if(put[i]) vec2.push_back(put[i]);
	}
	
	llint ans = 0;
	for(int i = 0; i < (int)vec2.size()-1; i++){
		ans += vec2[i]*vec2[i+1];
	}
	ans += vec2[0]*vec2.back();
	cout << ans << endl;
	
	return 0;
}