using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main(string[] args)

        {

            var r = new Regex("\\.");

            var result = r.Replace("<link rel=\"stylesheet\" href=\"27674557W.patent[DOT]001_files/27674557W[DOT]patent.00.css\" type=\"text/css\"/>", "[DOT]");

        Console.WriteLine(result);

        }

}