You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule N-(4-fluoro-2-methoxy-5-nitrophenyl)-4-(3-methylsulfonylbenzimidazol-3-ium-1-yl)pyrimidin-2-amine .
user
C19H16FN6O5S+
assistant