#include <iostream>
using namespace std;
int gt(int t)
{
	int tong = 1;
	for (int i = t; i >= 1; i--)
	{
		tong = tong*i;
	}
	return tong;
}
int tonggt(int a)
{
	int tonggt = 0;
	for (int i = a; i <= a; i--)
	{
		tonggt = tonggt + gt(a);
	}
	return tonggt;
}
int main()
{
	int a;
	cout << "Nhap a: ";
	cin >> a;
	cout << tonggt(a);
}