You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[4-(2-ethyl-3,4-dihydro-1H-isoquinoline-3-carbonyl)-1,4-diazepan-1-yl]-2-methoxyethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H29N3O3
assistant