Задача A. В ожидании Нового года

a.hs

import System.IO

type Timestamp = (Integer, Integer)

timeBeforeNewYear :: Timestamp -> Timestamp
timeBeforeNewYear (h, m)
    | m == 0    = (24 - h, m)
    | otherwise = (23 - h, 60 - m)

strToTimestamp :: String -> Timestamp
strToTimestamp s = (intList !! 0, intList !! 1)
    where intList = map (read :: String -> Integer) (words s)

timestampToStr :: Timestamp -> String
timestampToStr (h, m) = show h ++ " " ++ show m 

main = do
    line <- readFile "input.txt"
    let timestamp = strToTimestamp line
    writeFile "output.txt" (timestampToStr (timeBeforeNewYear timestamp))