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: import bisect
  
  H, W = map(int, input().split())
  ans = H * W
  for h in range(H):
      h1 = (H - h) // 2 if (H - h) % 2 == 0 else (H - h) // 2 + 1
      Smax = max(h * W, h1 * W)
      Smin = min(h * W, ((H - h) // 2) * W)
      ans = min(ans, Smax - Smin)
      w1 = W // 2 if W % 2 == 0 else W // 2 + 1
      Smax = max(h * W, (H - h) * w1)
      Smin = min(h * W, (H - h) * (W // 2))
      ans = min(ans, Smax - Smin)
  for w in range(W):
      w1 = (W - w) // 2 if (W - w) % 2 == 0 else (W - w) // 2 + 1
      Smax = max(H * w, H * w1)
      Smin = min(H * w, H * ((W - w) // 2))
      ans = min(ans, Smax - Smin)
      h1 = H // 2 if H % 2 == 0 else H // 2 + 1
      Smax = max(H * w, h1 * (W - w))
      Smin = min(H * w, (H // 2) * (W - w))
      ans = min(ans, Smax - Smin)
  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"}]