You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 5-[2-[(6-chloro-1,3-benzothiazol-2-yl)amino]-1,3-thiazol-4-yl]-1,3,3-trimethylindol-2-one by IUPAC nomenclature, provide its molecular formula.
user
C21H17ClN4OS2
assistant