You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule (2R)-2-[(8R,9S,10R,13S,17R)-14,17-dihydroxy-10,13-dimethyl-3-oxo-6,7,8,9,11,12,15,16-octahydrocyclopenta[a]phenanthren-17-yl]-2-hydroxyacetic acid into molecular formula.
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C21H28O6
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