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 Control.Monad
import Data.List
import Text.Printf

readInts :: IO [Int]
readInts = map read . words <$> getLine

main :: IO ()
main = do
  [x, y] <- sort <$> readInts
  when (y > 0) $ do
    printf "%d %d\n" x y
    main