static void Main(string[] args) { ParentClass p = new ParentClass(); ParentClass.NestedClass1 n1 = new ParentClass.NestedClass1(); ParentClass.NestedClass2 n2 = new ParentClass.NestedClass2(); ParentClass.NestedClass2.NestedClass3 n3 = new ParentClass.NestedClass2.NestedClass3(); p.f(); n1.f(); n2.f(); n3.f(); }