You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5S)-5-[3-fluoro-5-(2-pyridin-4-ylpyridin-4-yl)thiophen-2-yl]-2,5-dimethyl-1-methylidene-1-oxo-6H-1,2,4-thiadiazin-3-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H20FN5OS2
assistant