You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[2-(3,9-diazabicyclo[4.2.1]nonan-9-yl)-2-oxoethyl]-2-naphthalen-1-ylacetamide;hydrochloride by IUPAC nomenclature, provide its molecular formula.
user
C21H26ClN3O2
assistant