You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl (4R)-2-amino-4-(4-chlorophenyl)-6-phenyl-1,4-dihydropyrimidin-3-ium-5-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H19ClN3O2+
assistant