-- ref: https://yukicoder.me/submissions/474461

import           Text.Printf (printf)

main :: IO ()
main = do [p, q] <- map read . words <$> getLine
          printf "%.9f\n" $ solve p q

solve :: Double -> Double -> Double
solve p q = solve' 1 3.6e10
  where solve' :: Double -> Double -> Double
        solve' l r
          | abs f < eps = c
          | f < 0 = solve' c r
          | otherwise = solve' l c
          where c = (l + r) / 2
                f = c * c - q * c * logBase 2 c - p
                eps = 1e-6 :: Double