using System;

using Diacritics.Extensions;

using System.Linq;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        var problematicString = "ĐỖ THỊ LẬP";

        Console.WriteLine("Expected: DO THI LAP");

        Console.WriteLine("---------------------------------------------------");

        Console.WriteLine("Actual  : " +problematicString.RemoveDiacritics());

                 var santized = new string(problematicString.Where(c => CharUnicodeInfo.GetUnicodeCategory(c) != UnicodeCategory.NonSpacingMark)

     .ToArray());

        Console.WriteLine("Removed NonSpacingMark: "+ santized.RemoveDiacritics());

        Console.WriteLine("Fixed   : "+ santized.RemoveDiacritics().Replace('Đ','D'));

    }

}