You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl (4R)-4-[(8S,9S,10S,13R,14S,17R)-3-hydroxy-10,13-dimethyl-11-oxo-1,2,3,4,5,6,7,8,9,12,14,15,16,17-tetradecahydrocyclopenta[a]phenanthren-17-yl]pentanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C25H40O4
assistant