#include <iostream>
using namespace std;
int Fakt(unsigned int n) {
	int f = 1;
	for (int i = 1; i <= n; i++)
	{
		f *= i;
	}
	return f;
}
void Suma(unsigned int n, int &sum) {
	for (int i = 3; i <= n; i++)
	{
		if (i % 2 == 0)
			sum -= i * Fakt(i);
		else
			sum += i*Fakt(i);
	}
}
void main() {
	unsigned int n;
	int sum = 1;
	cin >> n;
	Suma(n, sum);
	cout << "Suma je: " << sum << endl;
}