You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-amino-3-[(3,4-dimethoxyphenyl)methyl]-8-(furan-2-yl)-1-methylpurino[7,8-b][1,2,4]triazol-2-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C20H19N7O4
assistant