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 2-[2-(methoxymethyl)benzimidazol-1-yl]-9-methyl-6-morpholin-4-ylpurine-8-carbaldehyde is given. What is its corresponding molecular formula?
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C20H21N7O3
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