You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2-[(3-chlorophenyl)methyl]-6-[2-(2-hydroxyethoxy)ethyl]-4,7-dimethyl-4a,9a-dihydropurino[7,8-a]imidazole-1,3-dione by IUPAC nomenclature, provide its molecular formula.
user
C20H24ClN5O4
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