/*************************************************************************
 * Name:
 * NetID:
 * Precept:
 *
 * Description: Takes an integer command-line argument n,
 * and prints n! = 1 * 2 * ... * n to standard output.
 *
 * Dependencies: None.
 *
 * Examples:
 * % java Factorial 0
 * 1
 * % java Factorial 1
 * 1
 * % java Factorial 5
 * 120
 * % java Factorial 12
 * 479001600
 * % java Factorial 20
 * 2432902008176640000
 *
 * Remarks:
 * - Would overflow a long if n > 20
 * - Need to use extended precision arithmetic to handle bigger factorials
 *************************************************************************/

public class Factorial {
    
    // recursive method to find factorial
    // assumes n >= 0 and n <= 20
    public static _______ factorial(_________________________) {

        // base case
        if (________________)
            return _________;

        // reduction step
        return ______ * factorial(________);
    }

    public static void main(String[] args) {
        int n = Integer.parseInt(args[0]);
        StdOut.println(factorial(n));
    }
}