You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-methyl-2-N-(2-methyl-6-propan-2-ylphenyl)-4-N-propan-2-ylpyrimidine-2,4-diamine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H26N4
assistant