You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 8-[(1-methoxy-1-oxopropan-2-yl)carbamoyl]-9-methyl-1,4-dioxaspiro[4.4]non-7-ene-9-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H21NO7
assistant