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.Foldable (for_)
import Data.Functor ((<$>))

main = do
  xs <- takeWhile (/= [0, 0]) . map (map read) . map words . lines <$> getContents
  for_ xs $ \[x, y] -> let zs = if x <= y then [x, y] else [y, x] in putStrLn $ unwords $ map show zs