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 N-(4-ethylphenyl)-2-[4-(4-fluorophenyl)-6-(trifluoromethyl)pyrimidin-2-yl]sulfanylacetamide using the IUPAC nomenclature.
user
C21H17F4N3OS
assistant