Problem:
Score : 300 points

Problem Statement

You are given three integers A, B and C. Find the minimum number of operations required to make A, B and C all equal by repeatedly performing the following two kinds of operations in any order:

Choose two among A, B and C, then increase both by 1.

Choose one among A, B and C, then increase it by 2.

It can be proved that we can always make A, B and C all equal by repeatedly performing these operations.

Constraints

0 \leq A,B,C \leq 50

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C

Output

Print the minimum number of operations required to make A, B and C all equal.

Sample Input 1

2 5 4

Sample Output 1

2

We can make A, B and C all equal by the following operations:

Increase A and C by 1. Now, A, B, C are 3, 5, 5, respectively.

Increase A by 2. Now, A, B, C are 5, 5, 5, respectively.

Sample Input 2

2 6 3

Sample Output 2

5

Sample Input 3

31 41 5

Sample Output 3

23

Solution in Ruby (2.3.3) (judge verdict: Accepted)

abc = gets.split(" ").map(&:to_i)

def check(abc, count=0)
  return count if abc[0] == abc[1] && abc[0] == abc[2]
  if abc.count(abc.min) == 2
    abc = abc.map do |a|
      if a == abc.min
        a+1
      else
        a
      end
    end
  else
    abc = abc.map do |a|
      if a == abc.min
        a+2
      else
        a
      end
    end
  end
  count += 1
  check(abc, count)
end

puts check(abc)