You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-benzyl-N-(3,4-difluorophenyl)-7-oxo-5-oxa-2,6-diazaspiro[3.4]octane-2-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H17F2N3O3
assistant