#include <stdio.h>
int main(void)
{
    int   i, n;
    long p=1;
    printf("Please enter n:");
    scanf("%d", &n);
    for (i=1; i<=n; i++)
    {
        p=p*i;                   
    }
    printf("%d! = %ld\n", n, p);
    return 0;
}