print("Hello, ESP32!")
from machine import Pin 
led1=(21,Pin.OUT)
led2=(22,Pin.OUT)
led3=(23,Pin.OUT)
while true:
    led1.on()
    sleep(0.5)
    led2.on()
    sleep(0.5)
    led3.on()
    sleep(0.5)
    led1.off()
    led2.off()
    led3.off()
    sleep(0.5)