You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 9-(2-methoxy-5-methylphenyl)-1,7-dimethyl-3-(2-methylprop-2-enyl)-4a,6,7,8-tetrahydropurino[7,8-a]pyrimidin-5-ium-2,4-dione is given. What is its corresponding molecular formula?
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C22H28N5O3+
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