Code for converting ppt/pps to pdf

public static int ConvertPowerPointToPDF()
        {
 string InputFilePath = @"C:\Users\\Desktop\tst1.pps";
            string OutputFilePath = @"C:\Users\\Desktop\tst1.pdf";
            int Errors = 0;
            Microsoft.Office.Interop.PowerPoint._Application PPApplication = null;
            Presentation PPDoc = null;


            try
            {

                // Start an instance of PowerPoint
                PPApplication = new Application();
                //PPApplication.Visible = True

                // Open the source document.
                PPDoc = PPApplication.Presentations.Open(InputFilePath);

                PPDoc.SaveAs(OutputFilePath, PpSaveAsFileType.ppSaveAsPDF);

                //PPDoc.ExportAsFixedFormat(OutputFilePath, PpFixedFormatType.ppFixedFormatTypePDF, PpFixedFormatIntent.ppFixedFormatIntentScreen, Microsoft.Office.Core.MsoTriState.msoCTrue, PpPrintHandoutOrder.ppPrintHandoutHorizontalFirst, PpPrintOutputType.ppPrintOutputBuildSlides, Microsoft.Office.Core.MsoTriState.msoFalse, , , , False, False, False, False, False)


            }
            catch (Exception ex)
            {

                //Interaction.MsgBox(ex.Message);
                //Errors = 1;

            }
            finally
            {
                // Close and release the Document object.
                if ((PPDoc != null))
                {
                    PPDoc.Close();
                    PPDoc = null;
                }

                // Quit PowerPoint and release the ApplicationClass object.
                if ((PPApplication != null))
                {
                    PPApplication.Quit();
                    PPApplication = null;
                }

                GC.Collect();
                GC.WaitForPendingFinalizers();
                GC.Collect();
                GC.WaitForPendingFinalizers();

            }

            return Errors;

        }
and to display the pdf file
protected void Page_Load(object sender, EventArgs e)
    {
        FileName ="tst1.pdf";
    }