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

swapTwoNumbers :: IO ()
swapTwoNumbers = do
  input <- getLine
  let xs = map read $ words input
  if (head xs == 0) && (head (tail xs) == 0)
    then do return ()
    else do putStrLn $ unwords $ map show $ sort xs
            swapTwoNumbers

main :: IO ()
main = swapTwoNumbers