Regarding Dr. Henden's comment: dwarf novae are usually intrinscially faint, nearby objects, so they will be less likely to be this reddened, unless these Sgr CVs are exceptionally intrinsically bright and heavily reddened. Assuming the intrinsic color, e.g. V-R=0, E(V-R) will become +1.0 according to Kiyota-san's observation. A(V) > 3 will place the object brighter than mag 10 at maximum. Assuming an average Mv=+4 for outbursting dwarf novae, the distance will be around 100 pc. The extinction of A(V)/d > 30 mag/kpc! is then needed. Regards, Taichi Kato