def get_neighbours(layout, x, y):

    neighbours = 0
    for dx in [-1,0,1]:
        for dy in [-1,0,1]:
            if dx == dy == 0:
                continue

            # Skip if we are outside of bounds
            if not 0 <= y+dy < len(layout):
                continue
            if not 0 <= x+dx < len(layout[y+dy]):
                continue

            if layout[y+dy][x+dx] != ".":
                neighbours += 1
    return neighbours



def walk_map(layout):

    free_roles = 0
    for y in range(0,len(layout)):
        for x in range(0, len(layout[y])):
            if layout[y][x] != ".":

                neighbours = get_neighbours(layout, x, y)

                if neighbours < 4:
                    free_roles += 1
                    layout[y][x] = "."
    return free_roles


def read_input(filename):
    layout = []
    for line in open(filename).read().splitlines():
        layout.append(list(line))
    return layout

# filename = "day04/example_input" # 43
filename = "day04/input" # 8013
layout = read_input(filename)

rolls = 1
removed_rolls = 0

while rolls > 0:
    rolls = walk_map(layout)
    removed_rolls += rolls

print(f"Total removed rolls: {removed_rolls}")