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;

public class Program

{

    public static void Main()

    {

        /*

        Regex.Replace( "Hello &145126451; mate!"  , "&.*?;","").Dump();

        "Hello &145126451; mate!".Replace(@"\\&.*?\\;","").Dump();

        string input = @"<a>

  <b name=""Example1""/>

  <b name=""Example2""/>

  <b name=""Example3""/>

  <b name=""Example4""/>

  <b name=""Example5""/>

  <b name=""Example6""/>  

</a>";

        XDocument doc= XDocument.Parse(input);

        doc.Descendants().ElementAt(1).Attributes().Select(x=>x.Name.LocalName).Dump(); 

        */

        List<DogOwner> dogowners = new List<DogOwner>() 

        {

            new DogOwner() {OwnerId = 1, Dogs = new List<Dog>() {new Dog(), new Dog()}},

            new DogOwner() {OwnerId = 2, Dogs = new List<Dog>() {new Dog(), new Dog()}}

        };

        List<CatOwner> catowners = new List<CatOwner>() 

        {

            new CatOwner() {OwnerId = 1, Cats = new List<Cat>() {new Cat(), new Cat()}},

            new CatOwner() {OwnerId = 2, Cats = new List<Cat>() { new Cat()}}

        };

        var results = dogowners.Select(x=> new Owner() {OwnerId = x.OwnerId, DogsCount = x.Dogs.Count()})

                 .Concat(catowners.Select(x=> new Owner() {OwnerId = x.OwnerId, CatsCount = x.Cats.Count()}))

                 .GroupBy(x=> x.OwnerId)

                 .Select(x=> new Owner() {OwnerId = x.Key, DogsCount = x.Sum(s=>s.DogsCount),  CatsCount = x.Sum(s=>s.CatsCount)}) 

                 .ToList();      

​

        results.Dump();

        Dictionary<int, Owner> owners = new Dictionary<int, Owner>();

        foreach(var dg in dogowners)

        {

            if(owners.ContainsKey(dg.OwnerId))

            {

                owners[dg.OwnerId].DogsCount += dg.Dogs.Count();

            }

            else 

            {

                owners.Add(dg.OwnerId, new Owner() 

                {

                    OwnerId = dg.OwnerId, 

                    DogsCount = dg.Dogs.Count()

                });

            }           

        }

​

        foreach(var ct in catowners)

        {

            if(owners.ContainsKey(ct.OwnerId))

            {

                owners[ct.OwnerId].CatsCount += ct.Cats.Count();

            }

            else 

            {

                owners.Add(ct.OwnerId, new Owner() 

                {

                    OwnerId = ct.OwnerId, 

                    CatsCount = ct.Cats.Count()

                });

            }           

        }

​

        owners.Values.Dump();

    }

}

​

public class DogOwner

{

    public int OwnerId {get;set;}

    public List<Dog> Dogs {get;set;}

}

​

​

public class CatOwner

{

    public int OwnerId {get;set;}

    public List<Cat> Cats {get;set;}

}

​

public class Owner

{

   public int OwnerId {get;set;}

   public int DogsCount {get;set;}

   public int CatsCount {get;set;}

}

​

public class Dog

{

}

​

public class Cat

{

}