So that's the thing that you have to leave on the right hand side of the sigmonotation. And if you've done the calculus playlist already, sigmonotation is really, it's kind of like a discrete integral on some level. Because in an integral, you're summing up a bunch of things, you're multiplying them times dx, which is a really small interval, but here you're just taking a sum. And that's what we showed in the calculus playlist, that an integral actually is kind of this infinite sum of infinitely small things, but I don't want to digress too much, but this was just a long way of saying that the sum from i equals 1 to n of the second term is the same thing as minus 2 times mu of the sum from i is equal to 1 to n of x sub i. And then finally, you have plus, well this is just a constant term, right? This is just a constant term, so you can take it out, times mu squared times the sum from i equals 1 to n. And what's going to be here? It's going to be a 1.