You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[[amino-(5,6,7,8-tetrahydronaphthalen-1-ylamino)methylidene]amino]-N-(5-methylpyridin-2-yl)propanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H25N5O
assistant