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: # 62c
  import math
  
  H, W = map(int, input().split())
  
  # 分け方は
  # 横 のみで分割
  # 縦 のみで分割
  # 縦→横 分割
  # 横→縦 分割　の4通り
  
  devided = [[1, 1], [1, 1], [1, 1]]
  ans = H * W
  
  
  def devision(dividend, divisor):  # 割られる数、割る数
      over = math.ceil(dividend / divisor)
      under = dividend // divisor
  
      if over == under:
          return over
      else:
          if abs(dividend / divisor - over) < abs(dividend / divisor - under):
              return over
          else:
              return under
  
  
  def calc_ans(list_of_devided):
      a = devided[0][0] * devided[0][1]
      b = devided[1][0] * devided[1][1]
      c = devided[2][0] * devided[2][1]
      # print(list_of_devided,a,b,c)
  
      if 0 in [a, b, c]:
          # print(H*W)
          return H * W
      else:
          # print(max(a,b,c) - min(a,b,c))
          return max(a, b, c) - min(a, b, c)
  
  
  # 横分割 ＝
  devided[0][1] = W
  devided[1][1] = W
  devided[2][1] = W
  devided[0][0] = devision(H, 3)
  devided[1][0] = devision(H - devided[0][0], 2)
  devided[2][0] = H - devided[0][0] - devided[1][0]
  if ans > calc_ans(devided):
      ans = calc_ans(devided)
  
  # 縦分割 ||
  devided[0][1] = devision(W, 3)
  devided[1][1] = devision(W - devided[0][1], 2)
  devided[2][1] = W - devided[0][1] - devided[1][1]
  devided[0][0] = H
  devided[1][0] = H
  devided[2][0] = H
  if ans > calc_ans(devided):
      ans = calc_ans(devided)
  
  # 縦→横 分割　├
  devided[0][1] = devision(W, 3)
  devided[0][0] = H
  devided[1][1] = W - devided[0][1]
  devided[2][1] = W - devided[0][1]
  devided[1][0] = devision(H, 2)
  devided[2][0] = H - devided[1][0]
  if ans > calc_ans(devided):
      ans = calc_ans(devided)
  
  # 横→縦　分割 ┬
  devided[0][1] = W
  devided[0][0] = devision(H, 3)
  devided[1][0] = H - devided[0][0]
  devided[2][0] = H - devided[0][0]
  devided[1][1] = devision(W, 2)
  devided[2][1] = W - devided[1][1]
  if ans > calc_ans(devided):
      ans = calc_ans(devided)
  
  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"}]