You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-(2-amino-3'-chloro-1'-fluorospiro[5,6-dihydro-1,3-oxazine-4,5'-chromeno[2,3-c]pyridine]-7'-yl)-5-chloropyridine-2-carboxamide into molecular formula.
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C21H14Cl2FN5O3
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