求1！+2！+.........N！

#include <stdio.h>
int main()
{
    int i,j=1;
    int n;
    int sum=0;
    scanf("%d",&n);
    for(i=1;i<=n;i++)
    {
        j=j*i;
        sum=j+sum;
    }

        printf("%d\n",sum);
        return sum;

}