You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-(2,2-difluoro-6-methyl-3H-1-benzofuran-5-yl)-N-[1-(3,5-difluoropyridin-4-yl)ethenyl]pyrazin-2-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H14F4N4O
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