You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 6-[(2-piperidin-1-ylpyridin-3-yl)methyl]-2-propan-2-yl-7,8-dihydro-5H-pyrido[4,3-d]pyrimidine by IUPAC nomenclature, provide its molecular formula.
user
C21H29N5
assistant