You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (E,2E)-2-(1,3-benzodioxol-5-ylmethylidene)-4-(4-iodo-1,3-benzodioxol-5-yl)-3-methoxycarbonylbut-3-enoic acid into molecular formula.
user
C21H15IO8
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