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
$i = 1;
while(true){
$x = trim(fgets(STDIN));
$a = explode(' ',$x);
$b = $a[0];
$s = $a[1];
    if ($b == 0 && $s == 0) break;
	if($b>$s){
		$temp = $b;
		$b = $s;
		$s = $temp;
		echo($b." ".$s). PHP_EOL;
	}else{
		echo($b." ".$s). PHP_EOL;
	}
	$i++;
}
exit;

?>