You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
8-(1,3-benzothiazol-2-ylsulfanyl)-3-methyl-7-[(3-methylphenyl)methyl]purine-2,6-dione The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H17N5O2S2
assistant