import sys
from typing import List, Optional, Tuple

removed_rolls = 0
file = '4.input' if len(sys.argv) <= 1 else sys.argv[1]
grid = list(map(list, map(str.strip, open(file).readlines())))

def check_occupied(y: int, x: int) -> Optional[Tuple[int, int]]:
    try:
        if x >= 0 and y >= 0 and grid[y][x] == "@":
            return (y, x)
    except IndexError: pass
    return None

def compute_adj(y: int, x: int) -> List[Optional[Tuple[int, int]]]:
    return [
        check_occupied(y-1, x-1), check_occupied(y-1, x), check_occupied(y-1, x+1),
        check_occupied(y, x-1), check_occupied(y, x+1),
        check_occupied(y+1, x-1), check_occupied(y+1, x), check_occupied(y+1, x+1)
    ]

def search_removable() -> List[Tuple[int, int]]:
    removable = []
    for y in range(len(grid)):
        for x in range(len(grid[y])):
            if grid[y][x] != "@": continue
            adj = compute_adj(y, x)
            if sum(map(bool, adj)) < 4:
                removable.append((y, x))
    return removable

removable = search_removable()
print(f'p1: {len(removable)}')

while len(removable):
    for (y, x) in removable:
        grid[y][x] = "."
    removed_rolls += len(removable)
    removable = search_removable()

print(f'p2: {removed_rolls}')