#!/usr/bin/env python3

import numpy as np
from scipy.signal import convolve

DIMS = 3
lines = [[(1 if x == '#' else 0) for x in x.strip()] for x in open("input.txt")]
grid = np.array(lines, dtype=np.byte)
grid = np.expand_dims(grid, axis=tuple(range(DIMS-2)))
kernel = np.ones((3, )*DIMS, dtype=np.byte)
kernel[(1, )*DIMS] = 0


for _ in range(6):
    grid = np.pad(grid, pad_width=1, mode='constant', constant_values=0)
    neighbors = convolve(grid, kernel, mode='same')
    set_inactive = np.logical_and(grid == 1, np.floor_divide(neighbors, 2) != 1)
    set_active = np.logical_and(grid == 0, neighbors == 3)
    grid[set_inactive] = 0
    grid[set_active] = 1
    for dim in range(DIMS):
        a = np.flatnonzero(grid.sum(axis=tuple(x for x in range(DIMS) if x != dim)))
        grid = grid[(slice(None),)*dim + (slice(min(a), max(a)+1),)]

print(np.sum(grid))