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 math
  
  
  def main():
      """
      H * W 板チョコ3分割
      面積：A B C
      minimize(max(A B C) - min(A B C))
  
      縦or横がMAX、片方が途中まで
      上記1つと、残りを半分
      残り：面積２以上
      """
      H, W = list(map(int, input().strip().split()))
      # 縦MAX, H>=2より、W-1まで確認
      # 横MAX, H>=2より、W=1のとき３分割できないので、W>=2
      answer = calc_answer(H, W)
      answer = calc_answer(W, H, answer=answer)
      print(answer)
  
  
  def calc_answer(H, W, answer=None):
      if answer is None:
          answer = float("inf")
  
      for _w in range(1, math.ceil(W / 2) + 1):
          # 縦MAXで試す
          S = [
              H * _w,
              H * math.ceil((W - _w) / 2),
              H * int((W - _w) // 2),
          ]
          if not 0 in S:
              S_diff = max(S) - min(S)
              # print(H, _w, S, S_diff, answer, sep="\t")
              answer = min(answer, S_diff)
  
          # 横MAXで縦分割
          S = [
              H * _w,
              (W - _w) * math.ceil(H / 2),
              (W - _w) * int(H // 2),
          ]
          if not 0 in S:
              S_diff = max(S) - min(S)
              # print(_h, _w, S, S_diff, answer, sep="\t")
              answer = min(answer, S_diff)
  
      return answer
  
  
  if __name__ == "__main__":
      main()
  
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"}]