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;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace _20170409_AOJ
{
    class Program
    {
        static void Main(string[] args)
        {
            string line;
            List<string> outList = new List<string>();
            for (; (line = Console.ReadLine()) != "";)
            {
                string[] sArr = line.Split(' ');
                int x = int.Parse(sArr[0]);
                int y = int.Parse(sArr[1]);

                if (x == 0 && y == 0)
                {
                    break;
                }

                if (x < y)
                {
                    outList.Add(string.Format("{0} {1}", x, y));
                }
                else
                {
                    outList.Add(string.Format("{0} {1}", y, x));
                }
            }

            foreach (var v in outList)
            {
                Console.WriteLine(v);
            }

            Console.ReadLine();
        }
    }
}