using System;
using System.Text.RegularExpressions;
using System.Linq;
using System.Collections.Generic;
public class Test
{
	public static void Main()
	{
		var txt = "[hel[[lo][qw[[qwe:]sdsdfsdf [note2]";
		var res = Regex.Matches(txt, @"\G\[[^]]*]").Cast<Match>().Select(p => p.Value).ToList();
		Console.WriteLine(string.Join("", res));
	}
}