You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(9S,13S)-13-ethyl-11-methylidenespiro[1,2,6,7,8,9,10,12,14,15,16,17-dodecahydrocyclopenta[a]phenanthrene-3,2'-1,3-dithiolane]-17-ol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H32OS2
assistant