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.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder sb=new StringBuilder();
        for(int i=1;i<3000;i++){
        	String items[]=reader.readLine().split(" ");
        	int num1=Integer.parseInt(items[0]);
        	int num2=Integer.parseInt(items[1]);
            if(num1==0 && num2==0){
            	break;
            }
        	if(num1<num2){
            	sb.append(Integer.toString(num1) + " " + Integer.toString(num2) + " \n");
        	}else{
            	sb.append(Integer.toString(num2) + " " + Integer.toString(num1) + " \n");
        	}
        }
        System.out.println(sb);
	}
}