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

public class Test
{
	public static void Main()
	{
		string pattern = @"([A-Za-z0-9.]+)|#([^#]+)#|\[([^][]+)]";
		string input = @"add galaxy [Milky way] elliptical 13.2B #test test #";
		string[] items = Regex.Split(input, pattern).Where(x => !string.IsNullOrWhiteSpace(x)).ToArray();
		
		foreach (string item in items)
		{
		    Console.WriteLine(item);
		}
	}
}