#!/usr/bin/env ruby
# frozen_string_literal: true

require_relative "grid"

class Main
  def run
    data = []
    $stdin.each_line do |line|
      data << line.chomp
    end

    @sum = 0

    grid = Grid.new(data)
    loop do
      grid_updated = false
      (0...grid.rows.size).each do |row_index|
        (0...grid.columns.size).each do |column_index|
          cell = grid.cell_at(row_index, column_index)
          next unless cell.value == "@"

          if cell.neighbours.count do |neighbour|
            neighbour.value == "@"
          end < 4
            data[row_index][column_index] = "x"
            @sum += 1
            grid_updated = true
          end
        end
      end

      break unless grid_updated
      grid = Grid.new(data)
    end

    puts @sum
  end
end

Main.new.run