You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(4-methylpiperazin-1-yl)-3-[7-(1,3-thiazol-5-yl)quinazolin-2-yl]propan-2-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H21N5OS
assistant