using System;

using System.Collections.Generic;

using System.Diagnostics;

using System.Linq;

public class Program

{

    private const string MyString = "thisismysuperstring:yurii:symbol:";

    public static void Main()

    {

        var generatedString = GenerateString();

        var stopwatch = new Stopwatch();

        stopwatch.Start();

        var strings = generatedString.Select(x => x.Replace(MyString, string.Empty)).ToList();

        stopwatch.Stop();       

        Console.WriteLine($"ElaplsedTime: {stopwatch.ElapsedMilliseconds}");

        foreach(var item in strings)

        {

            Console.WriteLine(item);

        }

    }

    private static ICollection<string> GenerateString()

    {

        var generatedString = new List<string>();

        for(var i = 0; i<100000; i++)

        {

            generatedString.Add($"{MyString}{i}");

        }

        return generatedString;

    }

}