So the only other location we can place C with respect to B is above B. So if we place gene C three units above B. That's going to be somewhere right over here. So this is our gene, C. And that works out mathematically because the distance between B, between B and C is three Map units and that's exactly what we want. And the distance between A and C, well, if this is five and this is three, that means the remaining is two Map units, right? Because five minus three is equal to two.