You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 2-[4-[2-(3-carboxypropanoylamino)-3-(3-methylbutylamino)-3-oxopropyl]phenoxy]propanedioic acid is given. What is its corresponding molecular formula?
user
C21H28N2O9
assistant