You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-methyl-N-[2-(2,2,3,3-tetrafluoro-1,4-benzodioxin-6-yl)phenyl]thiophene-2-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H13F4NO3S
assistant