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 PHP (judge verdict: Accepted)

<?php
while(true){
    $input = explode(" ",trim(fgets(STDIN)));
    $x = $input[0];
    $y = $input[1];
    if($x == 0 && $y == 0) break;
    if($x > $y){
        echo $y." ".$x."\n";
    } else {
        echo $x." ".$y."\n";
    }
}