You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-bromo-5-[4-[(2-chlorophenyl)methyl]piperazin-1-yl]-1-benzofuran-2-carboxylic acid The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H18BrClN2O3
assistant