You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 3-(1,3-dioxo-4H-isoquinolin-2-yl)-N-[(1R)-1-(furan-2-yl)ethyl]propanamide by IUPAC nomenclature, provide its molecular formula.
user
C18H18N2O4
assistant