You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-bromo-N-[3-(2-chlorobenzoyl)-5-[2-(4-methylpiperazin-1-yl)sulfonylethyl]thiophen-2-yl]acetamide into its molecular formula.
user
C20H23BrClN3O4S2
assistant