using System;

using System.Linq;

using System.Xml;                   

using System.Xml.Linq;

using System.Collections; 

using System.Collections.Generic;

using System.Data;

using System.Data.DataSetExtensions;

using System.Data.Linq;

using System.Text;

using System.Text.RegularExpressions;

using System.Xml.Serialization; 

using System.IO;

using System.Globalization;

using System.Diagnostics;

public class Program

{

    public static void Main()

    {

        string input = @"<products>

            <product>

                <territory>A</territory>

            </product>

            <product>

                <territory>B</territory>

            </product>

            <product>

                <territory>C</territory>

            </product>

            <product>

                <territory>D</territory>

            </product>

            <product>

                <territory>E</territory>

            </product>

        </products>";

        int position = 3;

        XElement element = XElement.Parse(input);

        element

            .Elements("product")

            .ElementAt(3)

            .Remove();

        element.ToString().Dump();  

    }

}