using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var locations = new List<Location>{new Location{Id = 1, UserId = 1, Name = "New York"}, new Location{Id = 2, UserId = 1, Name = "California"}, new Location{Id = 3, UserId = 1, Name = "Seattle"}, new Location{Id = 4, UserId = 1, Name = "New York"}, new Location{Id = 5, UserId = 2, Name = "Seattle"}, new Location{Id = 6, UserId = 2, Name = "Ontario"}, new Location{Id = 7, UserId = 3, Name = "Chicago"}, new Location{Id = 8, UserId = 4, Name = "Las Vegas"}, new Location{Id = 9, UserId = 5, Name = "New York"}, };

        var topLocations = locations.GroupBy(location => new

        {

        location.UserId, location.Name

        }

​

        ).Select(group => group.First()).GroupBy(location => location.Name).Select(group => new

        {

        group.Key, Count = group.Count()}

​

        ).OrderByDescending(location => location.Count).Take(2);

        foreach (var item in topLocations)

        {

            Console.WriteLine($"{item.Key} {item.Count}");

        }

    }

}

​

public class Location

{

    public int Id

    {

        get;

        set;

    }

​

    public int UserId

    {

        get;

        set;

    }

​

    public string Name

    {

        get;

        set;

    }

}