// D test program fact.d  CSE413 6/99, rev 5/00

// Read an integer k and print k!

// = n!
int fact(int n)
{
 if (! (n > 1))
   return 1;
 else
   return (n * fact(n - 1));
}


int main()
{
 int x; int fact;

 x = get();
 fact = fact(x);
 fact = put(fact);
 return 0;
}