We will try to derive this in the NA system. Assume its negation. By NIA and 2. By IC,1,4 and 10. I have been able to prove all axioms and derivation rules of that system, and in the book with this system the systems completeness is proved, so our system must be complete too - but we will prove that independently later.
All necessary theorems follows from the derivation rules.
The RH and its kinds C and IC can bud off new theorems without needing any older theorems. We can so to speak create all from nothing. The NA System.