You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule (1R,2S,3S,5R,7S,10S,11R)-7,11-dimethyl-14-oxopentacyclo[8.8.0.02,7.03,5.011,16]octadec-15-ene-6-carbonitrile ?
user
C21H27NO
assistant