You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as 4-[4-[(5-fluoro-2-methoxyphenyl)methyl]piperazin-4-ium-1-carbonyl]-2H-phthalazin-1-one using the IUPAC nomenclature.
user
C21H22FN4O3+
assistant