You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[4-[1-[4-(2-fluorobut-3-en-2-yloxy)phenyl]-1,2,4-triazol-3-yl]phenyl]methylideneazanium is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H18FN4O+
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