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-[2-(4-chlorophenyl)ethyl]-2-[[5-(3,4-dimethylanilino)-1,3,4-thiadiazol-2-yl]sulfanyl]acetamide into molecular formula.
user
C20H21ClN4OS2
assistant