You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[2-(3,4-dimethoxyphenyl)ethyl]-8-methoxy-1-(4-methoxy-3-propan-2-yloxyphenyl)-7-phenylmethoxychromeno[3,4-b]pyrrol-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C39H39NO8
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