getNput:: IO ()
getNput = do line <-getLine
             putStrLn line

getInt:: IO Int
getInt= do putStr "Unesi broj"
           line <-getLine
           return (read line :: Int)

sumInts:: IO Int
sumInts
    = do n <-getInt
         if n == 0
         then return 0
         else (do m <-sumInts
                  return (n+m))
sumabrojeva:: IO ()
sumabrojeva= do s <- sumInts
                print s