The compound shown is 1,2,3-trichlorocyclopropane drawn without stereochemistry. Treat the ring as planar and count configurational isomers only. How many stereoisomers does it have? Give an integer.

Each ring carbon carries one $\mathrm{Cl}$ and one $\mathrm{H}$. The only distinct arrangements are all three chlorines on the same face (all-cis) or two on one face and one on the other; any other pattern is one of these turned over. Both arrangements have a mirror plane (through one $\mathrm{CHCl}$ carbon and the midpoint of the opposite bond), so both are achiral. The total is 2 stereoisomers, with no enantiomeric pair.