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 4-[4-fluoro-2-[(2R)-2-hydroxycyclohexyl]oxyanilino]-5-methylthieno[2,3-d]pyrimidine-6-carboxamide is given. What is its corresponding molecular formula?
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C20H21FN4O3S
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