You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(3E,5E)-2-N-(1-cyclobutylideneethyl)-6-(4-fluorophenyl)hepta-1,3,5-triene-2,3-diamine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H23FN2
assistant