import java.util.Scanner;

class Fact {

    /* this function returns the factorial
     * of the parameter that is passed in */
    public static int fact(int x) {
        int f = 1;
        for (int i = x; i >= 0; i--) {
            f *= i;
        }

        return f;
    }

    /* main function to test out the factorial function above */
    public static void main(String args[]) {
        System.out.printf("Enter a number: ");
        Scanner in = new Scanner(System.in);
        int number = in.nextInt( );
        System.out.printf("%d! = %d\n", number, fact(number));
    }

}