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 N-(6-ethyl-4-oxothieno[2,3-d]pyrimidin-3-yl)-3-(2-methyl-3-oxo-1,4-benzoxazin-4-yl)propanamide is given. What is its corresponding molecular formula?
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C20H20N4O4S
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