You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 1-[(3R)-1-oxaspiro[4.4]nonan-3-yl]-3-[3-(2-oxo-1,3-oxazolidin-3-yl)phenyl]urea .
user
C18H23N3O4
assistant