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 methyl 3-amino-4-[(5-phenoxypyridin-3-yl)amino]thieno[2,3-b]pyridine-2-carboxylate is given. What is its corresponding molecular formula?
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C20H16N4O3S
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