from time import sleep
from threading import*

class Hello(Thread):
    def run(self):
        for i in range(500):
            print('Hello')
            sleep(1)

class hi(Thread):
    def run(self):
        for i in range(500):
            print('hi')
            sleep(1)


t1 = Hello()
t2 = hi()

t1.start()
sleep(0.2)
t2.start()