You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(2,3-dihydro-1H-inden-5-ylsulfonyl)-N-ethyl-N-(2-methylprop-2-enyl)piperidine-4-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H30N2O3S
assistant