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-[(1S)-1-(1H-benzimidazol-2-yl)ethyl]-3-methyl-4-oxo-1,5,6,7-tetrahydroindole-2-carboxamide ?
user
C19H20N4O2
assistant