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 (1S,4aS,7aR)-4a-hydroxy-7-methyl-1-[(2R,3R,4S,5S,6S)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy-1,7a-dihydrocyclopenta[c]pyran-5-one into molecular formula.
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C15H20O9
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