You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 2-[2-[2-[2-(4-ethoxyphenyl)-2-oxoethyl]tetrazol-5-yl]ethyl]isoindole-1,3-dione is given. What is its corresponding molecular formula?
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C21H19N5O4
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