You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5R)-5-ethyl-3-[6-[[(3S)-3-ethyl-1,3-dihydro-2-benzofuran-5-yl]oxy]pyridin-3-yl]-5-methylimidazolidine-2,4-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H23N3O4
assistant