You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-(6,7-dimethoxy-3,4-dihydro-1H-isoquinolin-2-yl)-N-(2-ethylphenyl)-1,2,4-triazin-3-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H25N5O2
assistant