You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 12-[1-(4-methoxypyrimidin-2-yl)piperidin-4-yl]-1,2,10,11-tetrazatricyclo[7.3.0.03,7]dodeca-2,7,9,11-tetraene into molecular formula.
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C18H21N7O
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