import machine
from machine import Pin

botA = Pin(18,Pin.IN,Pin.PULL_UP)
botB = Pin(4,Pin.IN,Pin.PULL_UP)
led = Pin(14,Pin.OUT)

while True:
    A = botA.value()
    B = botB.value()
    xor = (not A and B) or (A and not B)
    led.value(xor)