from threading import Thread
from queue import Queue
from time import sleep

sum = 0
access = 0 # Var for control who is allowed access for sum, start with 0 Thread
threads = 3
th_pool = []
is_live = [0] * threads

def worker(i):
	global sum, access, threads, th_pool, is_live
	th_pool.append(i)
	is_live[i] = 1
	# Wait until all threads is registred
	while len(th_pool) != threads:
		sleep(0.1)
	for _ in range(3):
		#sleep(threads)
		while access != i:
			sleep(0.1)
		sum += 1
		print(f'T{i} | {sum}')
		sleep(0.1)
		# Transfer access
		if len(th_pool) > 1:
			ind = th_pool.index(i)
			next = ind + 1
			if next > threads - 1:
				next = 0
			access = next
		else:
			access = i
	is_live[i] = 0

for i in range(threads):
	th = Thread(target = worker, args = (i,))
	th.start()

# Wait untill all ended
while is_live != [0] * threads:
	sleep(0.1)

print(f'\nSUM: {sum}')