You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 1-[(1S,2R,6R)-7-acetyl-2-(fluoren-9-ylidenemethyl)-7-bicyclo[4.1.0]hept-3-enyl]ethanone .
user
C25H22O2
assistant