def part1(fish):
    """
    Each lanternfish creates a new lanternfish once every 7 days
    New lanternfish need an extra 2 days for their first cycle
    7-day timer is 0-6

    How many lanternfish would there be after 80 days?
    """
    for day in range(80):
        for i in range(len(fish)):
            if fish[i] > 0:
                fish[i] -= 1
            else:
                fish[i] = 6
                fish.append(8)

    return len(fish)