poisk putei

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            var lolkek = new[] { "AB", "AE", "AF", "BF", "EF", "BE", "BC", "FC", "FD", "CD" };
            var azazaz = new[] { 'A','B','C','D','E','F'};
            var dictionary = new Dictionary<char, int>();
            foreach (var bukva in azazaz)
            {
                dictionary.Add(bukva,0);
            }
            dictionary['A'] = 1;
            for (int i = 0; i < lolkek.Length; i++)
            {
                foreach (var bukva in azazaz)
                {
                    if (bukva == lolkek[i][0])
                    {
                        //dictionary[bukva]++;
                        dictionary[lolkek[i][1]] += dictionary[bukva];
                    }
                }
            }
            Console.WriteLine(dictionary['D']);


        }

    }
}