import itertools
import string
from time import sleep


def combinations():
    for i in range(1, 4):
        yield from itertools.product(string.ascii_lowercase, repeat=i)


def step(g):
    tasks_list = []
    for i in range(1000):
        try:
            query = ''.join(next(g))
            tasks_list.append(query)
        except StopIteration:
            return None, None
    return check, tasks_list


g = combinations()
check = True

while check:
    check, list_tasks = step(g)
    print(list_tasks)