import Control.Monad
import Control.Applicative((<$>))

f (a,b) = if a < 0 || b < 0 then 0 else a * 1000 + b * 2000
main = do
	[c,d] <- map (read :: String -> Double) . words <$> getLine
	print $ maximum $ map f [(0, min (3.5*c) (1.2*d)), (min (4.0/3.0*c) (4*d), 0), ((5/7*c-2/7*d)*28/13, (-0.25*c+0.75*d)*28/13)]