You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3aS,4R,9bS)-7,9-dichloro-4-(4-nitrophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H14Cl2N2O2
assistant