Let's say it is a 1, 1, a 1, 2, all the way to a 1, n. And there's some row here, let's say that there's some row here on row i-- let's call this row i right here-- and here it has the terms x1, x2, all the way to xn, but everything else is just the regular a's. So then you have a-- let me make this as a21, all the way to a2n.