You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-(4-ethoxyphenyl)ethyl]-4-[3-(methylamino)-1H-1,2,4-triazol-5-yl]pyridin-2-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H22N6O
assistant