You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 2-[2-[2-(4-ethylphenyl)acetyl]imino-6-sulfamoyl-1,3-benzothiazol-3-yl]acetate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H23N3O5S2
assistant