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 JAVA (judge verdict: Wrong Answer)

import java.util.Scanner;

public class Main{
  
  public static void main(String[] args) {
    
    Scanner sin = new Scanner(System.in);

    int x = -1;
    int y = -1;
    while( (0 != (x = sin.nextInt())) && (0 != (y = sin.nextInt())) ) {
      if ( x <= y ) { System.out.println(x + " " + y); }
      else { System.out.println(y + " " + x);}
    }

    sin.close();
  }
}