using System;

using System.Linq;

using System.Collections.Generic;

using System.Collections;

public class Program

{

    public class Item 

    {

        public Item(int id, string elect1, string elect2)

        {

            Id = id;

            Elect1 = elect1;

            Elect2 = elect2;

        }

        public int Id {get;set;}

        public string Elect1 {get;set;}

        public string Elect2 {get;set;}

    }

    public static void Main()

    {

        Console.WriteLine("2 Most popular combinations are");

        var list = new System.Collections.Generic.List<Item> 

        {

            new Item (1,"FDI","AED"),

            new Item (2,"BPG","AED"),

            new Item (3,"AED","FDI"),

            new Item (4,"FDI","AED"),

            new Item (5,"GPH","AED"),

            new Item (6,"AED","BPG"),

            new Item (7,"GPH","FDI") 

        };

        var top2ByPopularity = list

            .GroupBy(x=> new {x.Elect1, x.Elect2})

            .Select(x=> new {x.Key, Count = x.Count()})

            .OrderByDescending(x=>x.Count)

            .Take(2)

            .Select(x=>x.Key);

        foreach (var item in top2ByPopularity)

        {

            Console.WriteLine(item.Elect1+" "+item.Elect2);

        }

    }

}