Problem:
Swapping Two Numbers

Write a program which reads two integers x and y, and prints them in ascending order.

Input

The input consists of multiple datasets. Each dataset consists of two integers x and y separated by a single space.

The input ends with two 0 (when both x and y are zero). Your program should not process for these terminal symbols.

Output

For each dataset, print x and y in ascending order in a line. Put a single space between x and y.

Constraints

0 ≤ x, y ≤ 10000

the number of datasets ≤ 3000

Sample Input

3 2
2 2
5 3
0 0

Sample Output

2 3
2 2
3 5

Solution in Haskell (judge verdict: Accepted)

import Data.List
import Data.List.Split
import Data.Char (isSpace)

trim :: String -> String
trim = f . f
  where
    f = reverse . dropWhile isSpace

calc :: Int -> Int -> (Int, Int)
calc a b = (min a b, max a b)

main :: IO ()
main = do
  s <- getContents
  let xs = splitOn "\n" $ trim s
  putStrLn $ intercalate "\n" [show a' ++ " " ++ show b' |
                               t <- xs,
                               let [a, b] = map read $ words t :: [Int],
                               a /= 0 || b /= 0,
                               let (a', b') = calc a b]