You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 5-[5-[(2R)-4-methyl-1-(2-phenoxyacetyl)piperazin-2-yl]-1,2,4-oxadiazol-3-yl]-1,3-dihydroindol-2-one by IUPAC nomenclature, provide its molecular formula.
user
C23H23N5O4
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