You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (4aR,5R)-3-[(4-chlorophenyl)methyl]-9-methoxy-N-(2-piperidin-1-ylethyl)-1,2,4,4a,5,6-hexahydropyrazino[1,2-a]quinoline-5-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C28H37ClN4O2
assistant