How to notate this relationship

UML
1

Hi there,

In the attachment there are two classes Item ansd Ledger.

Buiness rule say that :

  1. “Ledger” can have maximum of 12 “Item” objects
  2. In each “Item” object in the “Ledger” there can be maximum of 20 of the same item

Q:

  1. What kind of relationship is this?
  2. How do i put this in the class Diagram and how the references should be included into the classes?

cheers