You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 1-chloro-N-[4-[2-(2,4-difluorophenyl)-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazin-3-yl]pyridin-2-yl]cyclopropane-1-carboxamide by IUPAC nomenclature, provide its molecular formula.
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C21H17ClF2N4O2
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