You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(4,5-dimethyl-1H-pyrazol-3-yl)methyl]-6-(1-methylpyrazol-4-yl)sulfonylphthalazin-1-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H18N6O3S
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