You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(6R)-6-[(4-methylpiperazin-1-yl)methyl]-8-(pyridin-4-ylmethyl)-5,6,7,9-tetrahydroimidazo[1,2-a][1,4]diazepine The above is the IUPAC name of a molecule. Write its molecular formula.
user
C19H28N6
assistant