You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance (2R)-N-[(3aS,6aS)-3-(2,3-dihydro-1,4-benzodioxin-6-yl)-5,5-dioxo-3a,4,6,6a-tetrahydrothieno[3,4-d][1,3]thiazol-2-ylidene]-2-methylbutanamide .
user
C18H22N2O5S2
assistant