You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
diethyl 2-[[(6-ethyl-1,2-dihydroimidazo[2,1-b][1,3]benzothiazol-7-yl)amino]methylidene]propanedioate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H23N3O4S
assistant