import machine

led = machine.Pin(15,machine.Pin.OUT)

while True:
    user_input = input("Enter 'on' to turn LED on,'off' or 'quit' to stop:").strip().lower()

    if user_input == 'on':
        led.value(1)
        print("LED is ON")
    elif user_input == 'off':
        led.value(0)
        print("LED is OFF")
    elif user_input == 'quit':
        print("Exiting the program.")
        break
    else:
        print("invalid input!")