You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[(1R,4R,6S)-2-(6-methoxypyridine-3-carbonyl)-2-azabicyclo[2.2.1]heptan-6-yl]thiophene-2-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C18H19N3O3S
assistant