You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 3-N-[2-(4-chlorophenyl)ethyl]-5-N-[2-(2-fluorophenyl)ethyl]-1,2,4-triazine-3,5-diamine into its molecular formula.
user
C19H19ClFN5
assistant