You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 1-butyl-2-[[5-(4-fluoroanilino)-1,3,4-thiadiazol-2-yl]sulfanylmethyl]benzimidazole-5-sulfonamide is given. What is its corresponding molecular formula?
user
C20H21FN6O2S3
assistant