def brent(numbers):
    power = loop_length = 1
    tortoise = 0
    hare = 0

    while numbers[tortoise] != numbers[hare]:
        if power == loop_length:
            tortoise = hare
            power *= 2
            loop_length = 0
        hare += 1
        loop_length += 1

    position = 0
    tortoise = hare = 0

    for i in range(loop_length):
        hare += 1

    while numbers[tortoise] != numbers[hare]:
        tortoise += 1
        hare += 1
        position += 1

    return position, loop_length

numbers = [12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 11, 11, 11, 11]

print brent(numbers)