You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 1-(1,1-dioxo-4H-1lambda6,2,4-benzothiadiazin-3-yl)-4-(4-methyl-1,3-oxazol-2-yl)-4-phenylbutan-1-one ?
user
C21H19N3O4S
assistant