You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-[[4-(5-chloropyridin-2-yl)piperazin-1-yl]methyl]-2-N-(2-methoxyphenyl)-1,3,5-triazine-2,4-diamine is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H23ClN8O
assistant