You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-benzyl-3-[2-(6-oxocyclohexa-2,4-dien-1-yl)ethyl]-3,4-dihydroquinoxalin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H22N2O2
assistant