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 N-[3-[(4aS,7aS)-2-amino-4a-methyl-5,7-dihydro-4H-furo[3,4-d][1,3]oxazin-7a-yl]-4-fluorophenyl]-5-(2-fluoroprop-2-enoxy)pyrazine-2-carboxamide into molecular formula.
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C21H21F2N5O4
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