You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[5-[2-fluoro-5-[5-(6-methylpyridin-2-yl)-1H-pyrazol-4-yl]phenyl]-1H-imidazol-2-yl]ethyl methanesulfonate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H20FN5O3S
assistant