You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2-hydroxy-2-methyl-3-[[1-(2-phenylacetyl)-2,3-dihydroindol-6-yl]carbamoylamino]propanoic acid by IUPAC nomenclature, provide its molecular formula.
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C21H23N3O5
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