You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named (4R,4aS,8aR)-6-(furan-3-ylmethyl)-N-pyrazin-2-yl-2,3,4,4a,5,7,8,8a-octahydropyrano[3,2-c]pyridine-4-carboxamide is given. What is its corresponding molecular formula?
user
C18H22N4O3
assistant