You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule N-(3,5-dichloro-4-methylpyridin-2-yl)-2-[6-(4-fluorophenyl)thieno[3,2-d]pyrimidin-4-yl]sulfanylacetamide into molecular formula.
user
C20H13Cl2FN4OS2
assistant