You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(3-ethyl-2,5-dioxopyrrolidin-1-yl)-N-[2-[2-[2-[2-(3-oxobutoxy)ethoxy]ethoxy]ethoxy]ethyl]propanamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H36N2O8
assistant