You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[3-(4-chlorophenyl)-5,5-dioxo-3a,4,6,6a-tetrahydrothieno[3,4-d][1,3]thiazol-2-ylidene]-2-(4-fluorophenyl)acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H16ClFN2O3S2
assistant