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-[(5-ethyl-1,2,4-oxadiazol-3-yl)methylsulfanyl]-3-(furan-2-ylmethyl)-7-methyl-5,6,7,8-tetrahydro-[1]benzothiolo[2,3-d]pyrimidin-4-one is given. What is its corresponding molecular formula?
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C21H22N4O3S2
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