You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name [(3S,10S,13S)-10,13-dimethyl-11,17-dioxo-2,3,4,5,6,7,8,9,12,14,15,16-dodecahydro-1H-cyclopenta[a]phenanthren-3-yl] acetate ?
user
C21H30O4
assistant