You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[5-[2-(1,4-dioxa-8-azaspiro[4.5]decane-8-carbonyl)pyrrolidin-1-yl]-1,3,4-thiadiazol-2-yl]pyrrolidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H25N5O4S
assistant