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 Text.Printf

ans:: [Int] -> [Int]
ans x = sort x

main = do
    c <- getContents
    let i = map words $ lines c :: [[String]]
        j = map (map read) i :: [[Int]]
        k = takeWhile (/= [0,0]) j
        o = map ans k
    mapM_ (\x -> printf "%d %d\n" (x!!0) (x!!1)) o