You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 2-(furan-2-yl)-N-(furan-2-ylmethyl)-7-methyl-5,6,8,9-tetrahydropyrimido[4,5-d]azepin-4-amine .
user
C18H20N4O2
assistant