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-fluoro-N-[2-[(3-fluoro-4-methylbenzoyl)amino]ethyl]-3-(methoxymethyl)-1-benzothiophene-2-carboxamide is given. What is its corresponding molecular formula?
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C21H20F2N2O3S
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