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 (4aR,5R)-8-nitro-3-(2-oxo-2-pyrrolidin-1-ylethyl)-N-(2-phenylethyl)-1,2,4,4a,5,6-hexahydropyrazino[1,2-a]quinoline-5-carboxamide into molecular formula.
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C27H33N5O4
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