You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Can you give the molecular formula of the molecule (Z)-2-(4,4a,5,6,7a,11a-hexahydro-1H-pyrazino[2,1-d][1,5]benzoxazepin-6-yl)but-2-enedioic acid ?
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C16H18N2O5
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