You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2,4-difluoro-N-[2-methoxy-5-[4-methyl-2-(methylamino)thieno[2,3-d]pyrimidin-6-yl]pyridin-3-yl]benzenesulfonamide .
user
C20H17F2N5O3S2
assistant