We keep going all the way to this nth error. The nth error is going to be yn minus mxn plus b. And then we're going to square it. And then we are going to square it. So this is the squared error of a line. And I want to find, and what we're going to do over the next few videos, is I want to find the m and b that minimizes this value. That minimizes the squared error of this line right here.