You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2-[4-(carboxymethyl)-3,8-dioxo-1,4,6,9-tetraza-5-plumbaspiro[4.4]nonan-9-yl]acetic acid by IUPAC nomenclature, provide its molecular formula.
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C8H12N4O6Pb
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