You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Name the molecular formula for the molecule established as 2,4-difluoro-N-[5-(4-pyridin-3-ylthiophen-2-yl)pyridin-3-yl]benzamide using the IUPAC nomenclature.
user
C21H13F2N3OS
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