You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[2-(4-nitrophenyl)-2-oxoethyl]sulfanyl-5-(4-propan-2-ylphenyl)-3H-thieno[2,3-d]pyrimidin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H19N3O4S2
assistant