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 N-[3-(1H-benzimidazol-2-yl)propyl]-2-[(3S)-2,5-dioxo-3,4-dihydro-1H-1,4-benzodiazepin-3-yl]acetamide ?
user
C21H21N5O3
assistant