You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-(dimethylamino)ethyl]-N-(4-methylsulfonyl-1,3-benzothiazol-2-yl)-2-phenylacetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H23N3O3S2
assistant