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 3-(2-methylphenyl)-2-[(2R)-1-morpholin-4-yl-1-oxopropan-2-yl]sulfanylthieno[2,3-d]pyrimidin-4-one is given. What is its corresponding molecular formula?
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C20H21N3O3S2
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