You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (2S)-2-(N-methylsulfonylanilino)-N-(2-oxo-3-propan-2-yl-1,3-benzothiazol-6-yl)butanamide ?
user
C21H25N3O4S2
assistant