module Main where

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

average :: [Int] -> Double
average xs =
    (fromIntegral $ sum xs) / (fromIntegral $ length xs)

main :: IO ()
main = do
    ss <- fmap read . words <$> getLine :: IO [Int]
    let ans = average . tail . init $ sort ss
    printf "%.2f\n" ans