You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4S,6S)-4-[2-fluoro-5-[2-(2-methoxypyrimidin-5-yl)ethynyl]phenyl]-4-methyl-6-(trifluoromethyl)-1,3-oxazinan-2-amine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H18F4N4O2
assistant