You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(8S,9S,10R,13S,14S,17S)-17-acetyl-10,13-dimethyl-16-sulfonyl-2,6,7,8,9,11,12,14,15,17-decahydro-1H-cyclopenta[a]phenanthren-3-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H28O4S
assistant