You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[4-(2-aminoethylamino)-5-methylthieno[2,3-d]pyrimidin-2-yl]piperazine-1-carbaldehyde is the IUPAC name of a molecule. Please give its molecular formula.
user
C14H20N6OS
assistant