while (firstCharacter != -1)
            {
                firstCharacter = rtbTextPad.Text.IndexOf(Textt.findText, startIndex);
                lenghtText = Textt.findText.Length;
                secondCharacter = (firstCharacter + lenghtText) - 1;
                startIndex = secondCharacter;
                i++;
                System.Console.WriteLine("First occurrence: first:{0}, second:{1}, start:{2}, lenght:{3}", firstCharacter, secondCharacter, startIndex, lenghtText);
            }