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 Python (3.4.3) (judge verdict: Wrong Answer)

import math
a, b, c = map(int, input().split())
# 二つを +1　→　一つを -1 と読み替えて、目標値0 ~ 100までの操作回数を数える

def cnt(crnt, goal):
  if crnt >= goal:
    return abs(goal - crnt)
  else:
    return math.ceil((goal - crnt)/2) 

ans = 10**10
for i in range(100):
  ca = cnt(a, i)
  cb = cnt(b, i)
  cc = cnt(c, i)
  csum = ca + cb + cc
  if ans > csum:
    ans = csum
print(ans)