hornet command

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

public class StartUp
{
    static void Main()
    {

        Dictionary<string, List<string>> broadCasts = new Dictionary<string, List<string>>();
        Dictionary<string, List<string>> messages = new Dictionary<string, List<string>>();



        ReadInput(broadCasts,messages);
        PrintResult(broadCasts,messages);

    }

    public static void ReadInput(Dictionary<string,List<string>>broadCasts,Dictionary<string,List<string>>messages)
    {
        string input;
        while ((input = Console.ReadLine()) != "Hornet is Green")
        {
            if (input == null) continue;

            const string messagePattern = @"(^(\d+) \<\-\> ([a-zA-Z0-9]+))$";
            Regex message = new Regex(messagePattern);
            Match isMessage = message.Match(input);

            const string broadcastPattern = @"(\D+)\s(<->)\s([A-Za-z0-9]+)$";
            Regex broadcast = new Regex(broadcastPattern);
            Match isBroadcast = broadcast.Match(input);


            if (isMessage.Success)
            {
                GroupCollection messagePieces = isMessage.Groups;
                char[] personalCodeInput = messagePieces[2].Value.ToCharArray();
                Array.Reverse(personalCodeInput);
                string personalCode = string.Concat(personalCodeInput);
                string personalMessage = messagePieces[3].ToString();
                if (!messages.ContainsKey(personalCode))
                {
                    messages.Add(personalCode, new List<string>());
                }
                messages[personalCode].Add(personalMessage);

            }

            if (isBroadcast.Success)
            {
                GroupCollection broadcastPieces = isBroadcast.Groups;
                string broadcastInfo = broadcastPieces[1].Value;
                char[] broadcastFrequency = broadcastPieces[3].Value.ToCharArray();
                for (int i = 0; i < broadcastFrequency.Length; i++)
                {
                    char c = broadcastFrequency[i];
                    if (char.IsLetter(c))
                    {
                        var c1 = c <= 122 && c >= 97
                            ? char.ToUpper(c)
                            : char.ToLower(c);
                        broadcastFrequency[i] = c1;
                    }
                }
                string frequency = string.Concat(broadcastFrequency);
                if (!broadCasts.ContainsKey(frequency))
                {
                    broadCasts.Add(frequency, new List<string>());
                }
                broadCasts[frequency].Add(broadcastInfo);
            }
        }
    }
    public static void PrintResult(Dictionary<string,List<string>>broadCasts,Dictionary<string,List<string>>messages)
    {
        Console.WriteLine("Broadcasts:");
        if (!broadCasts.Any())
        {
            Console.WriteLine("None");
        }
        else
        {
            foreach (var br in broadCasts)
            {
                foreach (string m in br.Value)
                {
                    Console.WriteLine($"{br.Key} -> {m}");
                }
            }
        }
        Console.WriteLine("Messages:");
        if (!messages.Any())
        {
            Console.WriteLine("None");
        }
        else
        {
            foreach (var mm in messages)
            {
                foreach (var t in mm.Value)
                {
                    Console.WriteLine($"{mm.Key} -> {t}");
                }
            }
        }
    }
}