You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule (5S,8R,9S,10S,13S,14S)-3,10,13-trimethyl-1,2,3,4,5,6,7,8,9,11,12,14,15,16-tetradecahydrocyclopenta[a]phenanthren-17-one ?
user
C20H32O
assistant