<s>[INST] Now, give a code with the same functionality, but made in C#. [/INST] Here is an example of how to merge two PDF files in C# using the iTextSharp library:

```
using System;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;

namespace MergePDF
{
    class Program
    {
        static void Main(string[] args)
        {
            // Open the first PDF file
            PdfReader reader1 = new PdfReader("file1.pdf");

            // Open the second PDF file
            PdfReader reader2 = new PdfReader("file2.pdf");

            // Create a new PDF file to write the merged content
            Document document = new Document();
            PdfWriter writer = PdfWriter.GetInstance(document, new FileStream("merged.pdf", FileMode.Create));
            document.Open();

            // Add the pages of the first PDF file
            for (int i = 1; i <= reader1.NumberOfPages; i++)
            {
                PdfImportedPage page = writer.GetImportedPage(reader1, i);
                document.Add(Image.GetInstance(page));
            }

            // Add the pages of the second PDF file
            for (int i = 1; i <= reader2.NumberOfPages; i++)
            {
                PdfImportedPage page = writer.GetImportedPage(reader2, i);
                document.Add(Image.GetInstance(page));
            }

            // Close the PDF file
            document.Close();
            writer.Close();
        }
    }
}
```</s>