You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-methyl-6-methylsulfanyl-N-[2-(2-nitroanilino)ethyl]-2-propan-2-ylpyrimidine-5-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H23N5O3S
assistant