You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[(E)-(2,4-dimethoxyphenyl)methylideneamino]-3,4,5,6-tetrahydro-2H-azepin-7-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H21N3O2
assistant