import itertools

def product(*iters):
    inf_iters = tuple(itertools.cycle(enumerate(it)) for it in iters)
    num_iters = len(inf_iters)
    cur_val = [None for _ in xrange(num_iters)]

    first_v = True
    while True:
        i, p = 0, num_iters
        while p and not i:
            p -= 1
            i, cur_val[p] = inf_iters[p].next()

        if not p and not i:
            if first_v:
                first_v = False
            else:
                break

        yield tuple(cur_val)