And so this actually, I should actually write it like this. So we have a minus 2m times, once we distribute it out, here we're just going to be left with a y1 x1. Maybe I could call it an x1 y1. x1 y1, that's that over there with the 2m factored out. Plus x2, let me do that in another color. I want to make this easy to read. Plus x2 y2 plus xn yn.