using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;
using System.Xml;
using System.Xml.Linq;
public class MainClass {
public static void Main() {
XProcessingInstruction procInst;
XDocument xDocument = new XDocument(
new XElement("Books"),
procInst = new XProcessingInstruction("Book", "out-of-print"));
Console.WriteLine(xDocument);
procInst.Target = "BookContactManager";
procInst.Data = "update";
Console.WriteLine(xDocument);
}
}