using System;

using System.Linq;          

​

public class Program

{

    private const string PUNCHID_TEXT_KEY = "idmarca";

    public static void Main()

    {

        string texto = "IdMarca: 661764970 Marca:25-05-2022 01:00:00 user:2437306 Hora-Server:25-05-2022";

        //string texto = "Marca:25-05-2022 01:00:00 user:2437306 IdMarca:661764970 Hora-Server:25-05-2022";

        //string texto = "IdMarca:661764970";

        Console.WriteLine(Mejorado(texto));

    }

    private static long Mejorado(string key)

    {

        key = key.ToLower();

        //desde <c>PUNCHID_TEXT_KEY</c> se inicia a contar

        int end = key.IndexOf(PUNCHID_TEXT_KEY) + PUNCHID_TEXT_KEY.Length + 1; //agregamos uno para considerar ":"

        string nextValue = key.Substring(end);

​

        //intenta buscar el siguiente ":"

        int nextDotsIndex = nextValue.IndexOf(":");

        if (nextDotsIndex == -1)

        {

            //no hay mas valores a la derecha

            long.TryParse(new string(nextValue.Trim().Where(c => (Char.IsDigit(c) || c == '.' || c == ',')).ToArray()), out long cleanPunchId);

            return cleanPunchId;

        }

        string cleanedPunchIdText = new string(nextValue.Substring(0, nextDotsIndex).Trim().Where(c => (Char.IsDigit(c) || c == '.' || c == ',')).ToArray());

        long.TryParse(cleanedPunchIdText, out long punchId);

        return punchId;

    }

    private static long GetPunchId(string key)

    {

        string[] data = key.Split(':');

        long punchId = 0;

        for (int i = 0; i < data.Length; i++)

        {

            if (data[i].Contains(PUNCHID_TEXT_KEY))

            {

                i++;

                string[] data1 = data[i].Split(' ');

​

                punchId = long.Parse(data1[0]);

            }

        }

        return punchId;

    }

​

}