You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 1-benzylsulfonyl-N-[(2-ethoxypyridin-3-yl)methyl]piperidine-4-carboxamide is given. What is its corresponding molecular formula?
user
C21H27N3O4S
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