You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2-[(1S,2R)-2-aminocyclopentyl]-1-[4-[2-(4-methylphenyl)acetyl]piperazin-1-yl]ethanone;hydrochloride by IUPAC nomenclature, provide its molecular formula.
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C20H30ClN3O2
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