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What is the molecular formula of the compound with this IUPAC name (4S,7S,9Z,11aS)-7-(4-chloroanilino)-2,6-dioxo-3,4,7,8,11,11a-hexahydro-1H-pyrido[1,2-a]azocine-4-carboxylic acid ?
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C18H19ClN2O4
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