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: WA: Presentation Error)

import java.io.*;

public class Main{
    public static void main(String[]args)throws IOException{
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();
        while(true){

            String[] str = br.readLine().split(" ");
            int x = Integer.parseInt(str[0]);
            int y = Integer.parseInt(str[1]);

            if(x == 0 && y == 0){
                break;
            }else{
                sb.append(Integer.toString(x<y?x:y)).append(" ").append(Integer.toString(x<y?y:x)).append("\n");
            }

        }
        System.out.println(sb);
    }
}