You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-(4-cyclopropyl-7-fluoro-2,3-dihydroquinoxaline-1-carbonyl)-4-methoxy-1H-pyridin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H18FN3O3
assistant