You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name 11-acetyl-7,7,9-trimethyl-1,2,3,4,4a,5a,5b,11a-octahydro-[1]benzofuro[3,2-b]chromene-6,8-dione into its molecular formula.
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C20H24O5
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