using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

public class Program

{

    public static void Main()

    {

        List<Dictionary<string, long>> dictionaries = new()

        {

            new Dictionary<string, long>

            {

                { "A", 1 },

                { "B", 2 }

            },

            new Dictionary<string, long>

            {

                { "C", 3 },

                { "D", 4 }

            },new Dictionary<string, long>

            {

                { "E", 5 },

                { "F", 6 }

            },

            new Dictionary<string, long>

            {

                { "A", 7 },

                { "B", 8 }

            },

            new Dictionary<string, long>

            {

                { "C", 9 },

                { "D", 10 }

            },new Dictionary<string, long>

            {

                { "E", 11 },

                { "F", 12 }

            }

        };

        Dictionary<string, long> result = dictionaries.SelectMany(dict => dict).GroupBy(kvp => kvp.Key).ToDictionary(grp => grp.Key, grp => grp.Select(itm => itm.Value).Sum());

        foreach (KeyValuePair<string, long> pair in result)

        {

            Console.WriteLine($"{pair.Key}:{pair.Value}");

        }

    }

}