You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[3-[3-(2-fluoropyridin-4-yl)-1H-pyrrolo[2,3-b]pyridin-5-yl]-5-(trifluoromethyl)phenyl]but-2-enamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H16F4N4O
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