You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-(3,4-dihydro-1H-isoquinolin-2-yl)-5-methyl-N-(2-morpholin-4-ylethyl)pyrimidin-4-amine by IUPAC nomenclature, provide its molecular formula.
user
C20H27N5O
assistant