# Input: List of lines "<#>,<#>,<#>" (x,y,z coords of unit cubes)
# Output: Number of faces reachable from exterior

cubes = []

input_data = open(r"c:\users\edward\desktop\personal\aoc2022\18_input.txt")
for input_line in input_data.read().splitlines():
    input_line = input_line.replace("\n", "")
    coordinates = input_line.split(",")
    x, y, z = int(coordinates[0]), int(coordinates[1]), int(coordinates[2])
    cubes.append([x, y, z])

# All coordinates happen to be from 0 to 20
cells = []
for x in range(0, 21):
    cell_square = []
    for y in range(0, 21):
        cell_line = []
        for z in range(0, 21):
            if x in (0, 20) or y in (0, 20) or z in (0, 20):
                cell_line.append("water") # lava will overwrite this later
            else:
                cell_line.append("unknown")
        cell_square.append(cell_line)
    cells.append(cell_square)

for cube in cubes:
    cells[cube[0]][cube[1]][cube[2]] = "lava"

offsets = [
    [1, 0, 0],
    [-1, 0, 0],
    [0, 1, 0],
    [0, -1, 0],
    [0, 0, 1],
    [0, 0, -1]
]

while True:
    expanded_water = False
    for x in range(1, 20):
        for y in range(1, 20):
            for z in range(1, 20):
                if cells[x][y][z] == "unknown":
                    for offset in offsets:
                        x2, y2, z2 = x + offset[0], y + offset[1], z + offset[2]
                        if cells[x2][y2][z2] == "water":
                            cells[x][y][z] = "water"
                            expanded_water = True
                            break
    if not expanded_water:
        break

number_faces = 0
for cube in cubes:
    for offset in offsets:
        x, y, z = cube[0] + offset[0], cube[1] + offset[1], cube[2] + offset[2]
        if x < 0 or x > 20 or y < 0 or y > 20 or z < 0 or z > 20:
            number_faces += 1
        else:
            if cells[x][y][z] == "water":
                number_faces += 1

print (number_faces)