class Integer
  def layer
    ((Math.sqrt(self).ceil) / 2) + 1
  end

  def layer_first_corner
    (((self - 1) * 2) - 1)**2
  end

  def layer_length
    (self - 1) << 3
  end

  def layer_side_length
    layer_length >> 2
  end

  def layer_last_corner
    (self + 1).layer_first_corner
  end

  def layer_middles
    (0..3).map { |n| layer_first_corner + (layer_side_length >> 1) * ((2 * n) + 1) }
  end

  def layer_middles_offsets
    layer.layer_middles.map { |middle| (middle - self).abs }
  end

  def distance
    layer + layer_middles_offsets.min - 1
  end
end

n = STDIN.read.chomp.to_i
part_1 = n.distance
puts "Part 1: #{part_1}"