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-(2,4-dimethoxyphenyl)-2-(1-methyl-4-oxo-[1,2,4]triazolo[4,3-a]quinoxalin-5-yl)acetamide is given. What is its corresponding molecular formula?
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C20H19N5O4
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