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 3-[(6-chloro-7-ethyl-2-oxochromen-4-yl)methyl]-5-methyl-5-pyridin-2-ylimidazolidine-2,4-dione .
user
C21H18ClN3O4
assistant