using System;

using System.Text.RegularExpressions;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Regex reg = new Regex(@"Text +(?:100|[1-9]?[0-9])$"); // Text 1 to Text 100

        int count = 0;

        List<string> myTexts = new List<string>() {"Text 1", "Text 2", "Text 3", "Text 500"}; // Expected to count 3

        foreach (var myText in myTexts)

        {

            if(reg.IsMatch(myText))

                count++;

        }

        Console.WriteLine($"There are {count} matches in the list");

    }

}