with open("input.txt") as f:
    pond = [int(i) for i in f.read().strip().split(",")]

print("pond", pond)


def simulate():
    for i, fish in enumerate(pond[:]):
        # print("i, fish", i, fish)
        newfish = fish - 1
        if newfish < 0:
            newfish = 6
            pond.append(8)
        pond[i] = newfish


for i in range(0, 80):
    # print("pond", len(pond))
    simulate()

print("answer", len(pond))





# each lanternfish creates a new lanternfish once every 7 days.

# So, you can model each fish as a single number that represents the number of days until it creates a new lanternfish.

# a new lanternfish would surely need slightly longer before it's capable of producing more lanternfish: two more days for its first cycle.

# list of the ages of several hundred nearby lanternfish (your puzzle input).

# Find a way to simulate lanternfish. How many lanternfish would there be after 80 days?