N, K = gets.split.map(&:to_i)
S = (2 * N).times.map { gets.chomp }
C = (2 * N).times.map { gets.split.map(&:to_i) }
black_cnt = S.map { |row| row.count('#') }.sum

def greedy(take_cnt)
  p_que = []

  C.each do |row|
    row.each do |v|
      p_que << v
    end
  end

  p_que.sort.pop(take_cnt).sum
end

def solver_even(take_cnt)
  p_que = []

  0.upto(2 * N - 1) do |y|
    0.upto(N - 1) do |x|
      v = C[y][x] + C[y][2 * N - 1 - x]
      p_que << v
    end
  end

  p_que.sort_by! { |v| -v }
  val = 0

  take_cnt.times do
    v = p_que.shift

    val += v
  end

  val
end

values = []
values << greedy(black_cnt)
values << solver_even(black_cnt / 2) + K

puts values.max