public void AddToGraph(IntGraph graph)
 {
     foreach (var id in ConnectedIds)
     {
         graph.AddConnection(FromNodeId, id);
     }
 }
        static void Main()
        {
            var inputs = System.IO.File
                         .ReadAllLines(@"..\input.txt")
                         .Select(Input.ParseLine);

            var graph = new IntGraph();

            foreach (var inp in inputs)
            {
                inp.AddToGraph(graph);
            }

            var part1 = graph.Closure(0).Count;

            Console.WriteLine("Part 1: {0}", part1);

            var part2 = graph.Groups().Count();

            Console.WriteLine("Part 2: {0}", part2);

            Console.ReadLine();
        }