You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(2-methylpropyl)-4-oxo-N'-(2,3,4,5,6-pentafluorophenyl)phthalazine-1-carbohydrazide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H15F5N4O2
assistant