You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-[[1-[(1-methylimidazol-4-yl)methyl]azetidin-3-yl]methyl]-6-pyridin-4-ylpyridazin-3-one into molecular formula.
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C18H20N6O
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