You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2,3,5,6-tetramethylpyrazine;3,4,5,6-tetramethylpyridazine;2,4,5,6-tetramethylpyrimidine into its molecular formula.
user
C40H60N10
assistant