You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 4-(6-methyl-1H-benzimidazol-2-yl)-1-(7H-pyrrolo[2,3-d]pyrimidin-4-yl)piperidin-4-amine into its molecular formula.
user
C19H21N7
assistant