You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 5-(3,4-dihydro-2H-quinolin-1-yl)-N-[2-(4-methoxyphenyl)ethyl]-1,2,4-triazin-3-amine .
user
C21H23N5O
assistant