import Control.Applicative ((<$>))
import Text.Printf (printf)

solve :: RealFloat a => a -> a -> a
solve a b
    | c /= d = sqrt $ d * d - c * c
    | otherwise = sqrt $ c * c + d * d
    where
        c = min a b
        d = max a b

main :: IO ()
main = do
    [a, b] <- fmap read . words <$> getLine :: IO [Double]
    printf "%.12f\n" $ solve a b