You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (2S,3aS,6aS)-N-[(5-methylpyrazin-2-yl)methyl]-4-methylsulfonyl-2,3,3a,5,6,6a-hexahydrofuro[3,2-b]pyrrole-2-carboxamide into its molecular formula.
user
C14H20N4O4S
assistant