{-# LANGUAGE OverloadedStrings #-}

import qualified Data.ByteString.Char8 as C
import Data.Char
import Text.Printf

solve :: Int -> Int -> Double
solve a b
  | a == b    = sqrt $ x ** 2 + y ** 2
  | otherwise = sqrt $ x ** 2 - y ** 2
  where a2 = realToFrac a
        b2 = realToFrac b
        x  = max a2 b2
        y  = min a2 b2

main :: IO ()
main = do
  ss <- C.getLine
  let (a, ss2) = nextInt ss
  let (b, ss3) = nextInt ss2
  printf "%.20f\n" $ solve a b

nextInt :: C.ByteString -> (Int, C.ByteString)
nextInt ss
  | isDigit x || x == '-' = nextInt2 0 ss
  | otherwise             = nextInt $ C.tail ss
  where x = C.head ss
  
nextInt2 :: Int -> C.ByteString -> (Int, C.ByteString)
nextInt2 n ss
  | C.null ss = (n, ss)
  | y == '-'  = (-z,zs)
  | isDigit y = nextInt2 (n * 10 + (digitToInt y)) ys
  | otherwise = (n, ys)
  where y  = C.head ss
        ys = C.tail ss
        (z,zs) = nextInt2 0 ys