You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 5-(4-bromophenyl)-N-[4-chloro-3-(trifluoromethyl)phenyl]-6-ethylthieno[2,3-d]pyrimidin-4-amine .
user
C21H14BrClF3N3S
assistant