You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[4-(3,4-dichlorophenyl)piperazin-1-yl]-[(2R)-4-(2-methylbutan-2-yl)piperazin-2-yl]methanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H30Cl2N4O
assistant