def calc(stone)
    if (stone[0]!=0)
        return stone[0] + calc(stone.map{|e| e-stone[0]})
    elsif (stone[1]==0 || stone[2]<=2)
        return 0
    else
        k = stone[2] / 3
        return calc([k,stone[1],stone[2]-k*2].sort!)
    end
end

r,g,b = gets.split.map(&:to_i)

p calc([r,g,b].sort)