You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[2-(6-methoxynaphthalen-2-yl)morpholin-4-yl]-2-piperazin-1-ylethanone;hydrochloride by IUPAC nomenclature, provide its molecular formula.
user
C21H28ClN3O3
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