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

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

    loop do
      a, b, c = list

      count = [1, [b - a, (c-b)/2].min].max

      count = 0 if list.max - list.min == 1

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

      create = [0, list.min].max

      if zero_flag
        if create.zero?
          break
        else
          zero_flag = false
        end
      else
        if create.zero?
          zero_flag = create.zero?
        else
          zero_flag = false
        end
      end

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

    puts sum
  end
end

Yukicoder.new