You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2R)-2-[(2S)-3-acetyloxy-2-hydroxy-1-oxo-1-phenylmethoxypropan-2-yl]-4-methylpentanoic acid by IUPAC nomenclature, provide its molecular formula.
user
C18H24O7
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