You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name methyl 3-[5-[[(2R)-1-(benzylamino)-3-methyl-1-oxobutan-2-yl]amino]pyrazin-2-yl]prop-2-enoate into its molecular formula.
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C20H24N4O3
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