You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (4R,5R)-9-(cyclopropylmethyl)-2-(furan-2-ylmethyl)-4-pyridin-3-yl-6-oxa-2,9-diazaspiro[4.5]decan-10-one by IUPAC nomenclature, provide its molecular formula.
user
C21H25N3O3
assistant