You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named [[(3aS,4S,7S,7aS)-2-(4-methoxy-2-nitrophenyl)-1,3-dioxo-7,7a-dihydro-3aH-4,7-epoxyisoindol-4-yl]-acetyloxymethyl] acetate by IUPAC nomenclature, provide its molecular formula.
user
C20H18N2O10
assistant