#include<stdio.h>
int ans(int n)
{
	int sum = 1;
	for(int i = 4; i > 0; i--)
	{
		if (sum > 0)
		{
			sum = sum * n;
			n--;
		}
	}
	return sum;
}
int ansa(int n)
{
	int sum = 1;
	if (n > 0)
	{
		for (; n > 0; n--)
		{
			if (sum > 0)
			{
				sum = sum * n;
			}
		}
	}
	return sum;
}
int main()
{
	int n = 0;
	scanf("%d", &n);
	int sum = 0;
	sum = n + ans(n)/(24*ansa(n-4));
	printf("%d", sum);
	return 0;
}

求救啊