import Data.Char
import Data.List.Split
import Data.Maybe
import Text.Read


sep :: String -> [String]
sep s = concat $ map sepBr (splitOn " " s) where
    sepBr :: String -> [String]
    sepBr ""  = []
    sepBr " " = []
    sepBr word
        | a `elem` brackets = [[a]] ++ sepBr bc
        | c `elem` brackets = sepBr ab ++ [[c]]
        | otherwise         = ([a : bc])
        where a        = if word == [] then [] else head word
              b        = if word == [] then [] else init $ tail word
              c        = if word == [] then [] else last word
              ab       = [a] ++ b
              bc       = b ++ [c]
              brackets = ['(', ')']

main :: IO()
main = do
    putStrLn $ show $ sep "(+ 12 (* 3 4 (+ 1 2 3) 5) 1)"