You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by 1-[2-(2-chloropyridin-4-yl)-5-methoxypyrido[3,4-d]pyrimidin-4-yl]piperidine-3,4-diol ?
user
C18H18ClN5O3
assistant