You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-(2,6-difluorophenyl)cyclopropyl]-2-oxa-7-azaspiro[4.4]nonane-7-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H20F2N2O2
assistant