You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by methyl 2-[(3S)-8-amino-7-(3-methoxy-5-methylphenoxy)-2,5-dioxo-3,4-dihydro-1H-1,4-benzodiazepin-3-yl]acetate ?
user
C20H21N3O6
assistant