You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 5-N-(azetidin-3-yl)-7-(2-fluoro-6-methylphenyl)-1,2-dihydroisoquinoline-3,5-diamine by IUPAC nomenclature, provide its molecular formula.
user
C19H21FN4
assistant