You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-(3,4-dichlorophenyl)-N-(2-methoxyethyl)benzo[b][1,4]benzothiazepine-3-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C23H18Cl2N2O2S
assistant