You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(dimethylamino)-N-propan-2-yl-7-(pyridin-2-ylmethyl)-5,6,8,9-tetrahydropyrido[2,3-d]azepine-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H29N5O
assistant