You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(10-phenylspiro[acridine-9,9'-fluorene]-3'-yl)bicyclo[4.1.0]hepta-1(7),2,4-triene-3-carbonitrile is the IUPAC name of a molecule. Please give its molecular formula.
user
C39H24N2
assistant