output_description: Print the minimum possible value of S_{max} - S_{min}.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      H W
attempt: # -*- coding: utf-8 -*-
  import sys, math
  
  H, W = map(int, input().split(" "))
  
  
  def calc(a, b, c):
      tmp = (a[0] * a[1], b[0] * b[1], c[0] * c[1])
      return max(tmp) - min(tmp)
  
  
  result = H * W
  
  # H
  for i in range(H // 2 + 1):
      a = (i, W)
      hh = H - i
      rest = (hh, W)
  
      result = min(
          [
              result,
              calc(a, (hh // 2, W), (hh - hh // 2, W)),
              calc(a, (hh, W // 2), (hh, W - W // 2)),
          ]
      )
  
  # W
  for i in range(W // 2 + 1):
      a = (H, i)
      ww = W - i
      rest = (H, ww)
  
      result = min(
          [
              result,
              calc(a, (H // 2, ww), (H - H // 2, ww)),
              calc(a, (H, ww // 2), (H, ww - ww // 2)),
          ]
      )
  
  print(result)
  
problem_description: Statement
  
  There is a bar of chocolate with a height of H blocks and a width of W blocks.
  Snuke is dividing this bar into exactly three pieces. He can only cut the bar
  along borders of blocks, and the shape of each piece must be a rectangle.
  
  Snuke is trying to divide the bar as evenly as possible. More specifically, he
  is trying to minimize S_{max} \- S_{min}, where S_{max} is the area (the
  number of blocks contained) of the largest piece, and S_{min} is the area of
  the smallest piece. Find the minimum possible value of S_{max} - S_{min}.
samples: [{"input": "3 5", "output": "0\n    \n\nIn the division below, S_{max} - S_{min} = 5 - 5 = 0.\n\n![2a9b2ef47b750c0b7ba3e865d4fb4203.png](https://atcoder.jp/img/arc074/2a9b2ef47b750c0b7ba3e865d4fb4203.png)\n\n* * *"}, {"input": "4 5", "output": "2\n    \n\nIn the division below, S_{max} - S_{min} = 8 - 6 = 2.\n\n![a42aae7aaaadc4640ac5cdf88684d913.png](https://atcoder.jp/img/arc074/a42aae7aaaadc4640ac5cdf88684d913.png)\n\n* * *"}, {"input": "5 5", "output": "4\n    \n\nIn the division below, S_{max} - S_{min} = 10 - 6 = 4.\n\n![eb0ad0cb3185b7ae418e21c472ff7f26.png](https://atcoder.jp/img/arc074/eb0ad0cb3185b7ae418e21c472ff7f26.png)\n\n* * *"}, {"input": "100000 2", "output": "1\n    \n\n* * *"}, {"input": "100000 100000", "output": "50000"}]