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 Control.Applicative
import Data.List

main = do
  l <- lines <$> getContents
  let w = map words l :: [[String]]
  let wi = map (map (read :: String -> Int) ) w :: [[Int]]
  let s = map sort $ takeWhile (/= [0,0]) wi :: [[Int]]
  let ss = map (map show) s :: [[String]]
  let ss_cat = map unwords ss :: [String]
  mapM_ putStrLn ss_cat