gistfile1.hs

module Main where

import Control.Monad

data ExprTree = Var Char | Op ExprTree Char ExprTree

readExprS :: ReadS ExprTree

readExprS ('(':s) = do
        (l, op:s1 ) <- readExprS s
        (r, ')':t ) <- readExprS s1
        return ( (Op l op r), t )

readExprS (c:s) = [((Var c),s)]
    
instance Read ExprTree where
    readsPrec _ s = readExprS s

showsRPN :: ExprTree -> ShowS 
showsRPN (Var v) = (v:)
showsRPN (Op l op r) = showsRPN l . showsRPN r . (op:)

instance Show ExprTree where
    showsPrec _ t = showsRPN t


runTests :: Int -> IO()
runTests n = do
    expr <- getLine
    let tree = (read expr)::ExprTree
        in putStrLn $ show tree
    if n == 1 
        then return ()
        else do
            putStrLn ""
            runTests (n-1)

main :: IO()
main = do
    num <- liftM read getLine
    runTests num