You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[4-hydroxy-5-(4-oxo-3H-phthalazin-1-yl)cyclohexa-2,4-dien-1-yl]acetonitrile into its molecular formula.
user
C16H13N3O2
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