You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3'R,3'aS,4aR,6bS,7'aR,11aS,11bS)-3',6',10,11b-tetramethylspiro[1,2,4,4a,5,6,6a,6b,7,8,11,11a-dodecahydrobenzo[a]fluorene-9,2'-3a,4,5,6,7,7a-hexahydro-3H-furo[3,2-b]pyridine]-3-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C27H41NO2
assistant