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: # coding: utf-8
  import re
  import math
  from collections import defaultdict
  from collections import deque
  import collections
  from fractions import Fraction
  import itertools
  from copy import deepcopy
  import random
  import time
  import os
  import queue
  import sys
  import datetime
  from functools import lru_cache
  
  # @lru_cache(maxsize=None)
  readline = sys.stdin.readline
  sys.setrecursionlimit(2000000)
  # import numpy as np
  alphabet = "abcdefghijklmnopqrstuvwxyz"
  mod = int(10**9 + 7)
  inf = int(10**20)
  
  
  def yn(b):
      if b:
          print("yes")
      else:
          print("no")
  
  
  def Yn(b):
      if b:
          print("Yes")
      else:
          print("No")
  
  
  def YN(b):
      if b:
          print("YES")
      else:
          print("NO")
  
  
  class union_find:
      def __init__(self, n):
          self.n = n
          self.P = [a for a in range(n)]
          self.rank = [0] * n
  
      def find(self, x):
          if x != self.P[x]:
              self.P[x] = self.find(self.P[x])
          return self.P[x]
  
      def same(self, x, y):
          return self.find(x) == self.find(y)
  
      def link(self, x, y):
          if self.rank[x] < self.rank[y]:
              self.P[x] = y
          elif self.rank[y] < self.rank[x]:
              self.P[y] = x
          else:
              self.P[x] = y
              self.rank[y] += 1
  
      def unite(self, x, y):
          self.link(self.find(x), self.find(y))
  
      def size(self):
          S = set()
          for a in range(self.n):
              S.add(self.find(a))
          return len(S)
  
  
  def ispow(a, b):  # aはbの累乗数か
      now = b
      while now < a:
          now *= b
      if now == a:
          return True
      else:
          return False
  
  
  def getbin(num, size):
      A = [0] * size
      for a in range(size):
          if (num >> (size - a - 1)) & 1 == 1:
              A[a] = 1
          else:
              A[a] = 0
      return A
  
  
  def getfacs(n, mod_=0):
      A = [1] * (n + 1)
      for a in range(2, len(A)):
          A[a] = A[a - 1] * a
          if mod_ > 0:
              A[a] %= mod_
      return A
  
  
  def comb(n, r, mod, fac):
      if n - r < 0:
          return 0
      return (fac[n] * pow(fac[n - r], mod - 2, mod) * pow(fac[r], mod - 2, mod)) % mod
  
  
  def nextcomb(num, size):
      x = num & (-num)
      y = num + x
      z = num & (~y)
      z //= x
      z = z >> 1
      num = y | z
      if num >= (1 << size):
          return False
      else:
          return num
  
  
  def getprimes(n, type="int"):
      if n == 0:
          if type == "int":
              return []
          else:
              return [False]
      A = [True] * (n + 1)
      A[0] = False
      A[1] = False
      for a in range(2, n + 1):
          if A[a]:
              for b in range(a * 2, n + 1, a):
                  A[b] = False
      if type == "bool":
          return A
      B = []
      for a in range(n + 1):
          if A[a]:
              B.append(a)
      return B
  
  
  def isprime(num):
      if num <= 1:
          return False
      i = 2
      while i * i <= num:
          if num % i == 0:
              return False
          i += 1
      return True
  
  
  def ifelse(a, b, c):
      if a:
          return b
      else:
          return c
  
  
  def join(A, c=""):
      n = len(A)
      A = list(map(str, A))
      s = ""
      for a in range(n):
          s += A[a]
          if a < n - 1:
              s += c
      return s
  
  
  def factorize(n, type_="dict"):
      b = 2
      list_ = []
      while b * b <= n:
          while n % b == 0:
              n //= b
              list_.append(b)
          b += 1
      if n > 1:
          list_.append(n)
      if type_ == "dict":
          dic = {}
          for a in list_:
              if a in dic:
                  dic[a] += 1
              else:
                  dic[a] = 1
          return dic
      elif type_ == "list":
          return list_
      else:
          return None
  
  
  def pm(x):
      return x // abs(x)
  
  
  def inputintlist():
      return list(map(int, input().split()))
  
  
  ######################################################################################################
  
  H, W = inputintlist()
  ans = inf
  for a in range(1, H):
      A = a * W
      # 並行に分割
      B = ((H - a) // 2) * W
      C = H * W - A - B
      ans = min(ans, max([A, B, C]) - min([A, B, C]))
  
      # 垂直に分割
      B = (W // 2) * (H - a)
      C = H * W - A - B
      ans = min(ans, max([A, B, C]) - min([A, B, C]))
  
  H, W = W, H
  for a in range(1, H):
      A = a * W
      # 並行に分割
      B = ((H - a) // 2) * W
      C = H * W - A - B
      ans = min(ans, max([A, B, C]) - min([A, B, C]))
  
      # 垂直に分割
      B = (W // 2) * (H - a)
      C = H * W - A - B
      ans = min(ans, max([A, B, C]) - min([A, B, C]))
  
  
  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"}]