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 = list(map(int, input().split()))
  
  menseki = H * W
  _menseki = menseki
  ans = 100000000
  
  for i in range(0, H):
      menseki -= W
      _a = W * (i + 1)
      if i + 1 < H:
          m = W // 2 * (H - (i + 1))  # 縦切りの面積
          m2 = menseki - m
          buff_m = min(m, _a)
          buff_mx = max(m2, _a)
          # print('menseki ' + str(menseki))
          # print('m系')
          # # print(W//2, H-(i+1), m, m2)
          # print(buff_mx, buff_m, buff_mx-buff_m, ans)
          ans = min(ans, buff_mx - buff_m)
  
          # 横切りの面積
          _w = ((H - (i + 1)) // 2) * W
          _w2 = menseki - _w
          buff_w = min(_w, _a)
          buff_w2 = max(_w2, _a)
          # print('w系')
          # print(buff_w, buff_w2, buff_w2-buff_w, ans)
          ans = min(ans, buff_w2 - buff_w)
  
  menseki = _menseki
  H, W = (W, H)
  
  for i in range(0, H):
      menseki -= W
      _a = W * (i + 1)
      if i + 1 < H:
          m = W // 2 * (H - (i + 1))  # 縦切りの面積
          m2 = menseki - m
          buff_m = min(m, _a)
          buff_mx = max(m2, _a)
          # print('menseki ' + str(menseki))
          # print('m系')
          # # print(W//2, H-(i+1), m, m2)
          # print(buff_mx, buff_m, buff_mx-buff_m, ans)
          ans = min(ans, buff_mx - buff_m)
  
          # 横切りの面積
          _w = ((H - (i + 1)) // 2) * W
          _w2 = menseki - _w
          buff_w = min(_w, _a)
          buff_w2 = max(_w2, _a)
          # print('w系')
          # print(buff_w, buff_w2, buff_w2-buff_w, ans)
          ans = min(ans, buff_w2 - buff_w)
  
      # if menseki % 2 == 0:
      #     if menseki/2 <= _a:
      #         ans = min(ans, _a-(menseki//2))
      #     else:
      #         ans = min(ans, (menseki//2)-_a)
  
  
  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"}]