You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 2-[9-[(3S)-3-(5-methylfuran-2-yl)butyl]-3-oxo-2,9-diazaspiro[5.5]undecan-2-yl]acetic acid .
user
C20H30N2O4
assistant