Split One PDF Document to Multiple Files with C#, VB.NET

C# Code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Spire.Pdf;
namespace split_pdf
{
    class Program
    {
        static void Main(string[] args)
        {
            //open pdf document
           PdfDocument doc = new PdfDocument(@"C:\Program
 Files\e-iceblue\Spire.Pdf\Demos\Data\Sample3.pdf");
            //Split the PDF Document
            String pattern = "SplitDocument-{0}.pdf";
            doc.Split(pattern);
            String lastPageFileName
                = String.Format(pattern, doc.Pages.Count - 1);
            doc.Close();
            //Launching the Pdf file.
            System.Diagnostics.Process.Start(lastPageFileName);
        }
    }
}

Imports System;
Imports System.Collections.Generic;
Imports System.Linq;
Imports System.Text;
Imports Spire.Pdf;
Namespace split_pdf
    Friend Class Program
        Shared Sub Main(ByVal args() As String)
            'open pdf document
            Dim doc As New PdfDocument("C:\Program Files\e-iceblue\Spire.Pdf\Demos\Data\Sample3.pdf")
            'Split the PDF Document
            Dim pattern As String = "SplitDocument-{0}.pdf"
            doc.Split(pattern)
            Dim lastPageFileName As String = String.Format(pattern, doc.Pages.Count - 1)
            doc.Close()
            'Launching the Pdf file.
            Process.Start(lastPageFileName)
        End Sub
    End Class
End Namespace