def count_up_and_down():
    
    while True:
        try:
            number = int(input("Please enter a number: "))
            if number > 0:
                break
            else:
                print("The number must be a number. Try again.")
        except ValueError:
            print("That's not a valid number. Please try again.")

    for i in range(1, number + 1):
        print(i)

    
    for i in range(number, 0, -1):
        print(i)


count_up_and_down()