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 methyl 2-[(2R,4aR,12aS)-8-(cyclopropanecarbonylamino)-5-methyl-6-oxo-2,3,4,4a,12,12a-hexahydropyrano[2,3-c][1,5]benzoxazocin-2-yl]acetate into molecular formula.
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C21H26N2O6
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