class Yukicoder
  def initialize
    a, b, s = gets.chomp.split(' ').map(&:to_i)

    route1 = (s - a).abs + s
    route2 = (s - b).abs + (s - a) + a + ((a.zero?) ? 2 : 0)

    puts [route1, route2].min
  end
end

Yukicoder.new