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 6-methyl-N-[[(3R)-1-[2-(1-methylbenzimidazol-2-yl)ethyl]pyrrolidin-3-yl]methyl]pyridin-2-amine ?
user
C21H27N5
assistant