You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-N-[2-(furan-2-yl)-2-piperidin-1-ylethyl]-6,7-dimethoxyquinazoline-2,4-diamine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H27N5O3
assistant