You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 1-naphthalen-1-yl-3-[(1,4,6-trimethyl-3-oxo-2H-pyrazolo[3,4-b]pyridin-5-yl)methyl]urea ?
user
C21H21N5O2
assistant