Valid usernames

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;

public class Ex
{
    public static void Main()
    {
        string text = Console.ReadLine();
        string pattern = @"(?:^|\W)([a-z][\w]{2,24})";
        Regex regex = new Regex(pattern);
        MatchCollection matches = regex.Matches(text);

        int len = 0;
        int maxLen = int.MinValue;
        string firstUsername = "";
        string secondUsername = "";

        for (int i = 0; i < matches.Count - 1; i++)
        {
            len = matches[i].Groups[1].Length + matches[i + 1].Groups[1].Length;

            if (len > maxLen)
            {
                maxLen = len;
                firstUsername = matches[i].Groups[1].ToString();
                secondUsername = matches[i + 1].Groups[1].ToString();
            }
        }

        Console.WriteLine(firstUsername);
        Console.WriteLine(secondUsername);
    }
}