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 7-[3-[4-(3-chlorophenyl)piperazin-1-yl]propyl]-1,3-dimethylpurine-2,6-dione is given. What is its corresponding molecular formula?
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C20H25ClN6O2
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