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

public class Main {
    public static void main(String[] args) throws Exception {
        // Here your code !
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringBuilder builder = new StringBuilder();
        for (int i = 0; ; i++) {
            String input = br.readLine();
            String param[] = input.split(" ");
            int x = Integer.parseInt(param[0]);
            int y = Integer.parseInt(param[1]);
            if(x == 0 && y == 0){
               
                builder.deleteCharAt(4 * i - 1);
                break;
            }
            int max = Math.max(x, y);
            int min = Math.min(x, y);
            builder.append(min).append(" ").append(max).append("\n");
            
        }
        
        System.out.println(builder);
    }
}