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: h, w = map(int, input().split())
  res = float("inf")
  
  # H
  for i in range(1, h):
      s_h = [i * w]
      s_w = [i * w]
      # のこりは(h-i)*w
      # H
      s_h.append(((h - i) // 2) * w)
      s_h.append(((h - i) - (h - i) // 2) * w)
      if 0 in ((h - i) // 2, ((h - i) - (h - i) // 2), w):
          s_h.append(float("inf"))
      # print((h-i)//2,w)
      # print(((h-i)-(h-i)//2) , w)
      # print(s_h)
      # W
      s_w.append((h - i) * (w // 2))
      s_w.append((h - i) * (w - w // 2))
      if 0 in ((h - i), w // 2, (w - (w // 2))):
          s_w.append(float("inf"))
      # print((h-i) , w//2)
      # print((h-i) , (w - w//2))
      # print(s_w)
      res_h = max(s_h) - min(s_h)
      res_w = max(s_w) - min(s_w)
      res = min(res, res_h)
      res = min(res, res_w)
  
  # W
  for i in range(1, w):
      s_h = [h * i]
      s_w = [h * i]
      # のこりはh*(w-i)
      # H
      s_h.append((h // 2) * (w - i))
      s_h.append((h - (h // 2)) * (w - i))
      if 0 in ((h // 2), (w - i), (h - (h // 2))):
          s_h.append(float("inf"))
      # W
      s_w.append(h * ((w - i) // 2))
      s_w.append(h * ((w - i) - (w - i) // 2))
      if 0 in (h, ((w - i) // 2), ((w - i) - (w - i) // 2)):
          s_w.append(float("inf"))
      res_h = max(s_h) - min(s_h)
      res_w = max(s_w) - min(s_w)
      res = min(res, res_h)
      res = min(res, res_w)
  
  print(res)
  
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"}]