You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 15-[2-(4-hydroxyphenyl)ethenyl]-5-methyl-3,6,9-trioxatetracyclo[9.4.0.02,4.08,10]pentadeca-1(15),11,13-trien-12-ol into molecular formula.
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C21H20O5
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