import hashlib, threading, time

class Hasher(threading.Thread):
    def __init__(self, hasher):
        threading.Thread.__init__(self)
        self.setDaemon(True)
        self.hasher = hasher
        self.timer = time.time()
        self.start()
        
    def run(self):
        md = self.hasher
        buf = b'a'*10241
        while True:
            md.update(buf)
            self.timer = time.time()

threads = []
md = hashlib.md5()
for i in range(20):
    threads.append(Hasher(hashlib.md5()))

while True:
    print(len([t for t in threads if abs(time.time() - t.timer) > 1]))
    time.sleep(0.5)