C语言代码

#include <stdio.h>
int main()
{
	unsigned long long int s = 0, factorial = 1;
	int n, count1, count2;
	scanf("%d", &n);
	for (count1 = 1; count1 <= n; count1++)
	{
		for (count2 = 1; count2 <= count1; count2++)
		{
			factorial *= count2;
		}
		s += factorial;
		factorial = 1;
	}
	printf("%llu", s);
	return 0;
}

能帮忙看一下哪里有错吗？ 我不知道怎么设定高精度