Raspberry pie 4B parsing PWM

#!/usr/bin/env python

import RPi.GPIO as GPIO
import time

pin=18

GPIO.setmode(GPIO.BCM)
GPIO.setup(pin, GPIO.IN)

while True:    
    # Wait for the low level to end , Then record the time 
    while GPIO.input(pin) == 0:  # Capture the rising edge of the signal output 
        pass
    time1 = time.time()  
    
    # Wait for the high level to end , Then record the time 
    while GPIO.input(pin) == 1:  # Capture the falling edge of signal end output 
        pass
    time2 = time.time() 
    # Wait for the low level to end , Then record the time 
    while GPIO.input(pin) == 0:  # Capture the rising edge of the signal output 
        pass
    time3 = time.time()
    #print(time1)
    #print(time2)
    #print(time3)
    
    period = time3 - time1
    high_time = time2 - time1
    low_time = time3 - time2
    duty_cycle = (int)(high_time * 100 / period*100)
    print(duty_cycle)
    time.sleep(0.1)
    #print("-------------------------")