You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 7-fluoro-6-(1-hydroxy-3-oxo-3a,4,7,7a-tetrahydro-1H-isoindol-2-yl)-4-(2-methylprop-2-enyl)-1,4-benzoxazin-3-one .
user
C20H21FN2O4
assistant