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())
  ch1 = h // 3
  ch2 = ch1 + 1
  cw1 = w // 3
  cw2 = cw1 + 1
  ans = float("inf")
  
  # ch1で切ってwの真ん中で切る。
  s = [0, 0, 0]
  s[0] = ch1 * w
  yoko1 = w // 2
  yoko2 = w - yoko1
  s[1] = (h - ch1) * yoko1
  s[2] = (h - ch1) * yoko2
  temp = max(s) - min(s)
  ans = min(ans, temp)
  # ch2で切ってwの真ん中で切る。
  s = [0, 0, 0]
  s[0] = ch2 * w
  yoko1 = w // 2
  yoko2 = w - yoko1
  s[1] = (h - ch2) * yoko1
  s[2] = (h - ch2) * yoko2
  temp = max(s) - min(s)
  ans = min(ans, temp)
  # 全部横
  s = [0, 0, 0]
  s[0] = ch1 * w
  tate1 = (h - ch1) // 2
  tate2 = h - ch1 - tate1
  s[1] = tate1 * w
  s[2] = tate2 * w
  temp = max(s) - min(s)
  ans = min(ans, temp)
  
  # 全部縦
  s = [0, 0, 0]
  s[0] = cw1 * h
  yoko1 = (w - cw1) // 2
  yoko2 = w - cw1 - yoko1
  s[1] = yoko1 * h
  s[2] = yoko2 * h
  temp = max(s) - min(s)
  ans = min(ans, temp)
  
  # cw1で切ってhの真ん中で切る。
  s = [0, 0, 0]
  s[0] = cw1 * h
  tate1 = h // 2
  tate2 = h - tate1
  s[1] = (w - cw1) * tate1
  s[2] = (w - cw1) * tate2
  temp = max(s) - min(s)
  ans = min(ans, temp)
  
  # cw2で切ってhの真ん中で切る。
  s = [0, 0, 0]
  s[0] = cw2 * h
  tate1 = h // 2
  tate2 = h - tate1
  s[1] = (w - cw2) * tate1
  s[2] = (w - cw2) * tate2
  temp = max(s) - min(s)
  ans = min(ans, temp)
  
  
  print(ans)
  
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"}]