You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-ethoxy-1-[1-(5-methoxy-1-methylpyrazole-3-carbonyl)-2,3,4,4a,5,7,8,8a-octahydro-1,6-naphthyridin-6-yl]ethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H28N4O4
assistant