You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name [5-(cyclopropylmethoxy)pyrazin-2-yl]-[(5R,7S)-7-ethyl-2,6-dioxa-9-azaspiro[4.5]decan-9-yl]methanone into its molecular formula.
user
C18H25N3O4
assistant