public class InFact
{
   private static long getFactorial( long n )
   {
      return n > 1 ? n * getFactorial( n - 1 ) : 1;
   }
 
   private static double getInverseFactorial( long n )
   {
      return 1.0 / getFactorial(n);
   }
 
   public static void main (String args[])
   {
      long NUM = 5;
      try
      {
         if( args.length == 1 )
            NUM = Integer.parseInt(args[0]);
      }
      catch( java.lang.NumberFormatException nfe )
      {
         System.out.println( "Try specifying an integer value next time." );
      }
 
      System.out.println( "The factorial of " + NUM + 
                          " is " + getFactorial(NUM) +
                          ", the \"inverse factorial\" is " +
                          getInverseFactorial(NUM) + "." );
   }
}