You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (2S,3aS,7aS)-6-(6-methylpyridazin-3-yl)-N-(thiophen-2-ylmethyl)-3,3a,4,5,7,7a-hexahydro-2H-furo[2,3-c]pyridine-2-carboxamide ?
user
C18H22N4O2S
assistant