from machine import Pin 
import time 
led1=Pin(23,Pin.OUT)
led2=Pin(22,Pin.OUT)
led3=Pin(21,Pin.OUT)
buzzer=Pin(18,Pin.OUT)
btn=(18.Pin.IN)
while True:
    if btn.value==0:
     led1.on()
     led2.off()
     led3.off()
     buzzer.value(1)
     time.sleep(0.5)
     led1.on()
     led2.on()
     led3.off()
     buzzer.value(1)
     time.sleep(0.5)
     led1.on()
     led2.on()
     led3.on()
     buzzer.value(1)
     time.sleep(0.5)
     else:
     led1.off()
     led2.off()
     led3.off()
     buzzer.value(0)
     time.sleep(0.5)