// An equivalent client program. No using clauses.
// In source file client-equiv.cs


/*
  Namespace N1
    public class C1
  Namespace N2
    internal class C2 
    public class C3 
    Namespace N3
      public class C4
*/


// No using clauses - instead fully qualified class names:

public class Client{
  N1.C1 v = new N1.C1(); 

  // The type or namespace name 'C2' could not be found.
  // N2.C2 w = new N2.C2();   
  N2.C3 x = new N2.C3(); 
  N2.N3.C4 y = new N2.N3.C4(); 
}