You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 6-methyl-N-(2-methyl-3,4-dihydro-1H-isoquinolin-7-yl)-1H-benzimidazole-4-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C19H20N4O
assistant