module Main where

import Data.List (sortBy)

type Input  = [Int]
type Output = Int

parse :: String -> Input
parse =
    map read
    . words
    . (!! 1)
    . lines

solve :: Input -> Output
solve =
    loop 0 0
    . sortBy (flip compare)
    where
    loop _ acc [] = acc
    loop i acc xs
        | length xs < 2 ^ i = acc + i * sum xs
        | otherwise =
              let
                  (a, b) = splitAt (2 ^ i) xs
              in
                  loop (succ i) (acc + i * sum a) b

render :: Output -> String
render =
    show

main :: IO ()
main =
    interact
        ( render
        . solve
        . parse
        )