public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        int replynr;

        System.out.println("Starting number: ");
        replynr = keyboard.nextInt();

        while (true) {
            if (replynr % 2 == 0) {
                replynr /= 2;
                System.out.println(replynr);
                if (replynr == 1) {
                    break;
                }
            }
            if (replynr % 2 == 1) {
                replynr = replynr * 3 + 1;
                System.out.println(replynr);
                if (replynr == 1) {
                    break;
                }
            }
        }
    }