#include <stdio.h>

/* 题目如下

 * S = 1 + 2! + 3! + ... + N!

 */

int main(int argc, char *argv[])

{

    int s = ;

    int n = ;

    int i = ;

    int m = ;

    printf("Please input N :");

    if (scanf("%d",&n) ==  ){

        while (i <= n ){

            m *= i++;

            s += m;

        }

        printf("The result is %d \n", s);

    }

    else

        printf("Input Error.\n");

    return ;

}