You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1R,2S,5S,6S,10R,20S)-8-cyano-1,2,6,10,17,17,20-heptamethyl-7,13-dioxotetracyclo[12.8.0.02,11.05,10]docosa-8,11-diene-20-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C31H43NO4
assistant