You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4S)-4-[(2R)-5-methoxy-2-methyl-2,3-dihydro-1-benzofuran-7-yl]-1,4-dihydro-[1,3,5]triazino[1,2-a]benzimidazol-2-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H19N5O2
assistant