How to calculate nRTCI?

Hello Experts.

Given this:

nRTCI: This is the Target NR Cell Identifier. It consists of NR Cell Indentifier (NCI) and Physical Cell Identifier of the target NR Cell (nRPCI).

The NRRelation.nRTCI identifies the target cell from the perspective of the NRCell, the name-containing instance of the subject NRCellCU instance.

How we exactly calculate nRTCI?