You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 6-bromo-4-methoxy-N-[(1-oxo-2-oxa-8-azaspiro[4.5]decan-3-yl)methyl]pyrazolo[1,5-a]pyridine-3-carboxamide is given. What is its corresponding molecular formula?
user
C18H21BrN4O4
assistant