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 (2S)-2-[3-(7,8-dimethoxy-4-methyl-2-oxochromen-3-yl)propanoylamino]-4-methylsulfanylbutanoic acid is given. What is its corresponding molecular formula?
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C20H25NO7S
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