import threading
import time

num = 0
lock = threading.Lock()

def task1(x):
    global num
    lock.acquire()
    for i in range(x):
        num += 1
        print("task1","task1","task1")
    lock.release()
    # time.sleep(3)


def task2(x):
    global num
    with lock:
        for i in range(x):
            num -= 1
            print("task2","task2","task2")
        # time.sleep(3)




def main():
    t1 = threading.Thread(target=task1, args=(100,))
    t2 = threading.Thread(target=task2, args=(100,))

    t1.start()
    t2.start()

    t1.join()
    t2.join()

    print("½á¹û£º", num)


if __name__ == '__main__':
    main()