module Main where

import Control.Applicative
import Control.Monad
import Data.List (sort)
import Text.Printf (printf)

median :: [Int] -> Double
median as
    | r == 0    = (fromIntegral . sum . take 2 $ drop (q - 1) bs) / 2
    | otherwise = fromIntegral (bs !! q)
  where
    bs = sort as
    (q, r) = length as `divMod` 2

main :: IO ()
main = do
    getLine
    as <- fmap read . words <$> getLine
    printf "%.1f\n" (median as)