[t001] factorial

#include <stdio.h>
#include <stdlib.h>
long long fact(long long n)
{
    if(n==0)
        return 1;
    else
        return (n*fact(n-1));
}
int main()
{
    long long n;
    scanf("%lld",&n);
    printf("%lld",fact(n));
    return 0;
}