You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[3-(2,4-difluorophenyl)-5,5-dioxo-3a,4,6,6a-tetrahydrothieno[3,4-d][1,3]thiazol-2-ylidene]-2-(2-methoxyphenyl)acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H18F2N2O4S2
assistant