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 C# (judge verdict: Accepted)

using System;

class Untitled
{
	static void Main(string[] args)
	{
		// ???????????´??° x, y ?????????????????????????????????????°?????????????????????????????????°??????????????????????????????
		// x, y???0????????????
		bool parsed = false;
		int a = 0, b = 0;
		string s = null;
		while (!string.IsNullOrEmpty (s = Console.ReadLine ())) {
			string[] strs = s.Split (' ');
			if (strs.Length >= 2) {
				parsed = Int32.TryParse (strs [0], out a);
				if (parsed) {
					parsed = Int32.TryParse (strs [1], out b);
				}
			}

			if (parsed) {
				if (a == 0 && b == 0)
					break;
				if (a < b) {
					System.Console.WriteLine (a + " " + b);
				} else {
					System.Console.WriteLine (b + " " + a);
				}
			}
			parsed = false;
			a = b = 0;
			s = null;
		}
	}
}