You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3S,8R,9S,10R,11R,12S,13S,14S,17S)-17-[(1S)-1-hydroxyethyl]-10,13-dimethyl-1,2,3,4,7,8,9,11,12,15,16,17-dodecahydrocyclopenta[a]phenanthrene-3,11,12,14-tetrol is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H34O5
assistant