You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule octyl 5-methyl-7-pyridin-4-yl-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxylate into molecular formula.
user
C20H27N5O2
assistant