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-[2-[3-[(5-methyl-2-pyridin-3-ylimidazol-1-yl)methyl]piperidin-1-yl]-2-oxoethyl]pyrrolidin-2-one ?
user
C21H27N5O2
assistant