You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[6-[(3S)-4-ethyl-3-methylpiperazin-1-yl]pyridin-3-yl]-4-propan-2-ylbenzenesulfonamide;hydrochloride The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H31ClN4O2S
assistant