求1!+2!+3!+4!，，，+10!的值

#include <stdio.h>

int main()
{
	int i = 0;
	int sum = 0;
	int ret = 1;
	int n = 0;
	scanf("%d", &n);
	for (i = 1; i <= n; i++)
	{
		ret = ret * i;
		sum += ret;
	}
	printf("%d\n", sum);
	return 0;
}