You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [(2R,4aR,8aS)-1,2,3,4,4a,5,6,7,8,8a-decahydronaphthalen-2-yl] (3S)-1-butanoylpiperidine-3-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C20H33NO3
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