output_description: Print the minimum number of operations required to make A, B and C all equal.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      A B C
attempt: import collections
  
  visited = set()
  
  
  def is_goal(nums):
      A, B, C = nums
      return A == B == C
  
  
  def bfs(nums):
      q = collections.deque()
      visited.add(nums)
      q.append(nums + (0,))
  
      if is_goal(nums):
          return 0
  
      while len(q) != 0:
          n = q.popleft()
  
          if is_goal(n[:3]):
              return n[3]
  
          for i in range(3):
              new_n = list(n[:])
              for j in range(3):
                  if i != j:
                      new_n[j] += 1
              new_n[3] += 1
              new_n = tuple(new_n)
              if new_n[:3] not in visited:
                  visited.add(new_n[:3])
                  q.append(new_n)
  
          for i in range(3):
              new_n = list(n[:])
              new_n[i] += 2
              new_n[3] += 1
              new_n = tuple(new_n)
              if new_n[:3] not in visited:
                  visited.add(new_n[:3])
                  q.append(new_n)
  
      return -1
  
  
  A, B, C = map(int, input().split())
  
  print(bfs((A, B, C)))
  
problem_description: 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.
samples: [{"input": "2 5 4", "output": "2\n    \n\nWe can make A, B and C all equal by the following operations:\n\n  * Increase A and C by 1. Now, A, B, C are 3, 5, 5, respectively.\n  * Increase A by 2. Now, A, B, C are 5, 5, 5, respectively.\n\n* * *"}, {"input": "2 6 3", "output": "5\n    \n\n* * *"}, {"input": "31 41 5", "output": "23"}]