You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule 1,2,3,4,5,6,7,8,9,9a-decahydroquinolizin-5-ium-1-ylmethyl 2-oxochromene-3-carboxylate into molecular formula.
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C20H24NO4+
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