You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named ethyl 4-[(3R)-1-(2-methoxy-5-methylphenyl)sulfonylpiperidine-3-carbonyl]piperazine-1-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C21H31N3O6S
assistant