two and I'll just tell you that that we're using the same sort of optimality result that was in the proof to be able to set that threshold between once you give me the two prices I can set the optimal threshold right and what you find is that if you now plot how dynamic pricing does using these two prices the two prices from the extremes then yeah it degrades badly outside of that uncertainty set but inside the uncertainty set and what we can show is that dynamic pricing always gets you at least the linear interpolation between