from machine import*
from time import*
ledr=Pin(14,Pin.OUT)
ledb=Pin(21,Pin.OUT)
ser=PWM(Pin(17,mode=Pin.OUT))
ser.freq(50)
while True:
    ser.duty(75)
    for i in range(5):
        ledr.on()
        ledb.off()
        sleep(0.2)
        ledr.off()
        ledb.on()
        sleep(0.2)
    ledb.off()
    ser.duty(27)
    sleep(3)