You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named (6R)-1-(2-methylpropyl)-6-phenylmethoxy-4-[(3S)-thiolan-3-yl]-1,4-diazepan-2-one by IUPAC nomenclature, provide its molecular formula.
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C20H30N2O2S
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