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