using System.Collections;
using System.Collections.Generic;

namespace Tree
{
  public class ClassA
  {

    public List<ClassB> B
    {
      get { return b; }
    }

    public List<ClassC> C
    {
      get { return c; }
    }

    public IEnumerable BC
    {
      get
      {
        foreach (ClassB b in B)
        {
          yield return b;
        }

        foreach (ClassC c in C)
        {
          yield return c;
        }

      }
    }

    public string Name
    {
      get { return "A"; }
    }

    private List<ClassB> b = new List<ClassB>();
    private List<ClassC> c = new List<ClassC>();
  }
}