You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 4-[(4-chlorophenyl)methyl]-6-hydroxy-2-(1-methylpiperidin-1-ium-4-yl)phthalazin-1-one;chloride .
user
C21H23Cl2N3O2
assistant