You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3aR,4R,7R,7aS)-2-[1-[(2,4-dichlorophenyl)methyl]pyrazol-4-yl]-3a,4,5,6,7,7a-hexahydro-4,7-epoxyisoindole-1,3-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H15Cl2N3O3
assistant