string input = "AB-ABC-2-300A", output = "";
            int num = Convert.ToInt32(input[7]) + 1;
            for (int i = 0; i < 7; i++)
            {
                output = (output + (Convert.ToString(input[i])));
            }
            output = output + num;

            for (int i = 8; i < input.Length; i++)
            {
                output = (output + (Convert.ToString(input[i])));
            }
            Console.WriteLine(output);