You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(1-methylsulfonylpyrrolidin-3-yl)methyl]-7-oxa-1,3-diazaspiro[4.4]non-1-en-4-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C12H19N3O4S
assistant