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: Wrong Answer)

A = gets.strip.split.map(&:to_i)
A.sort!

if (A[2]-A[1]) % 2 == (A[2]-A[0]) % 2

    if  (A[2]-A[1]) % 2 == 0

        puts (A[2]-A[1]) / 2 + (A[2]-A[0]) / 2

    else

        puts (A[2]-A[1]) / 2 + (A[2]-A[0]) / 2 + 1

    end

else

    if (A[2]-A[1]) % 2 == 0

        puts (A[2]-A[1]) / 2 + (A[2]-A[0]-1) / 2 + 1

    else 

        puts  (A[2]-A[1]-1) / 2 + (A[2]-A[0]) / 2 + 1
        
    end

end