import Data.List
median :: [Integer] -> Float
median xs | mod l 2 == 0 = fromIntegral(xs!!(div l 2) + xs!!((div l 2)-1)) / 2
		  | otherwise    = fromIntegral(xs!!(div l 2))
		where l = length xs

main = do
	getLine
	getLine >>= print . median . sort . map read . words