You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(E)-2-cyano-3-[2-(4-ethylpiperazin-1-yl)-9-methyl-4-oxopyrido[1,2-a]pyrimidin-3-yl]-N-prop-2-enylprop-2-enamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C22H26N6O2
assistant