You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named benzyl N-[(2S)-1-[(3aR,6aR)-2,3,3a,5,6,6a-hexahydrofuro[3,2-b]pyrrol-4-yl]-4-methyl-1-oxopentan-2-yl]carbamate by IUPAC nomenclature, provide its molecular formula.
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C20H28N2O4
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