You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1,4-dioxa-8-azaspiro[4.5]decan-8-yl-[5-(4-methylphenyl)pyrazolidin-3-yl]methanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H25N3O3
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