-- import Prelude hiding (abs)
import Control.Monad
import Control.Arrow ((&&&))
import Data.List (nub, sort, group, find)
import Data.Maybe (fromMaybe, fromJust)
import qualified Data.IntMap as M

type Counter = M.IntMap Int

main :: IO ()
main = do
    [h, w] <- (map read . words) <$> getLine
    print $ solve (h,w)

-- |
--
-- >>> solve (3,5)
-- 0
--
-- >>> solve (4,5)
-- 2
--
-- >>> solve (5,5)
-- 4
--
-- >>> solve (100000, 2)
-- 1
solve :: (Int,Int) -> Int
solve (h,w) = minimum $ map (calc (h,w)) $ yxs1 ++ yxs2
  where
    yxs1 = [(y,w) | y <- [1 .. (h-1)]]
    yxs2 = [(h,x) | x <- [1 .. (w-1)]]


calc :: (Int,Int) -> (Int,Int) -> Int
calc (h,w) (y,x) = maximum ss - minimum ss
  where ss = splitRect3 (h,w) (y,x)

splitRect3 :: (Int,Int) -> (Int,Int) -> [Int]
splitRect3 (h,w) (y,x)
  | h == y = y * x : splitRect2 (h, w - x)
  | w == x = y * x : splitRect2 (h - y, w)

splitRect2 :: (Int,Int) -> [Int]
splitRect2 (h,w)
  | dh > dw   = [h * w1, h * w2]
  | otherwise = [w * h1, w * h2]
  where
    h1 = h `div` 2
    h2 = h - h1
    w1 = w `div` 2
    w2 = w - w1
    dh = abs (h1 - h2) * w
    dw = abs (w1 - w2) * h
