You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[2-carbamoyl-5-(5,6-dimethoxybenzimidazol-1-yl)thiophen-3-yl] 3-methyl-2-nitrobenzenesulfonate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H18N4O8S2
assistant