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

public class Test
{
	public static void Main()
	{
    		Console.WriteLine(string.Join(", ", ExtractListId("GET_LIST 1000 10001 10002")));
	}
	
	private static string pattern = @"^GET_LIST(?:\s+([A-Za-z0-9]{4,10})){0,100}$";
	private static List<string> ExtractListId(string command)
	{
	    return Regex.Matches(command, pattern)
			.Cast<Match>().SelectMany(p => p.Groups[1].Captures
				.Cast<Capture>()
				.Select(t => t.Value)
			)
			.ToList();
	}
}