using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

public class Program

{

    public static void Main()

    {

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

        {

            new Dictionary<string, string>

            {

                { "A", "a" },

                { "B", "b" }

            },

            new Dictionary<string, string>

            {

                { "C", "c" },

                { "D", "d" }

            },new Dictionary<string, string>

            {

                { "E", "e" },

                { "F", "f" }

            },

            new Dictionary<string, string>

            {

                { "A", "a" },

                { "B", "b" }

            },

            new Dictionary<string, string>

            {

                { "C", "c" },

                { "D", "d" }

            },new Dictionary<string, string>

            {

                { "E", "e" },

                { "F", "f" }

            }

        };

        Dictionary<string, string> newDict = new();     

​

        foreach(var dict in dictionaries){

             foreach (var kvp in dict)

             {

                 if (newDict.ContainsKey(kvp.Key))

                 {

                     newDict[kvp.Key] += kvp.Value;

                 }

                 else

                 {

                     newDict.Add(kvp.Key, kvp.Value);

                 }

             }

        }

        foreach(KeyValuePair<string, string> pair in newDict)

        {

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

        }

    }

}