You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7-[4-(3-chlorophenyl)piperazine-1-carbonyl]-5-ethylpyrazolo[1,5-a]quinoxalin-4-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C23H22ClN5O2
assistant