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

    list = [r,g,b].sort
    sum = 0

    loop do
      a, b, c = list

      count = [b - a, (2+c-b)/2].min

      list[0] += count
      list[2] -= 2 * count

      create = list.min

      break if create.zero?

      sum += create
      list = list.map{|i| i - create}.sort
    end

    puts sum
  end
end

Yukicoder.new