using System;

using System.Linq;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        string[] array = {"Tomas, Tomaš", "Denis"};

        var keyword = "Tomas";

        var stringComp = StringComparer.InvariantCultureIgnoreCase;

        var names = array.Where(str=>stringComp.Compare(str, keyword)>=0);

        foreach(var n in names){

            Console.WriteLine(n);

        }

    }

}