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.util.Scanner;

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

        while(true) {
            int x = stdIn.nextInt();
            int y = stdIn.nextInt();

            if (x>y) {
                int n = x;
                x = y;
                y = n;
            } else if (x == 0 && y == 0) {
                break;
            }

            sb.append(x).append(" ").append(y).append("\n");
        }
        System.out.println(sb);
    }
}