 OK, so I guess Billy wants to do this problem. Let's try it. So we've got this cyclic ether, and we're reacting with H i, halo-helic acid, so with excess. So the first thing that's going to happen, these things are very strong acids, especially H i. I is a very big anion, so it's going to protonate fairly well, going to do that. In fact, the reason that you want H i is because eventually the I is going to add to the thing. So the first step is that keep your stereochemistry. How do we do this? Well, in this case, right now, nothing has actually changed in stereochemistry. Now we've got that protonated ether, and we've got I minus. OK, so now you've got a question as to what's going to happen. Two things that can happen, right? One of them is going to happen more quickly than the other one is going to happen. You can't imagine, well, the only one thing that's going to happen is going to happen. You can't imagine this going like that, right? But what's that going to give the primary carbocation? So two things, two things, so that is definitely not going to happen, right? So you have two options. This thing can attack some of them. Where can it attack? It can attack on this side, or it can attack on this side. Is it going to attack on this side? Why not? Yeah, it's a quaternary center. So this is not very sterically hindered at all. So not only is it going to not just lose that bond, that carbon-oxygen bond, it's going to take what type of reaction is this thing called? SN2 reaction, right? Your favorite reaction. So when we do that, so this is what I was talking about. When you do that, remember, just keep your stereochemistry, especially you guys. I don't care what confirmation you draw this thing. So just draw it how it is. So once we got our stereochemistry, there, we're cool. So notice there was no change in stereochemistry. What it attacked here, it would have, but it can't attack that because of the steric hindrance. The other thing is, again, we thought, well, maybe we could lose that first. Can it do that? No. Why? Because we'd make the primary carbocation, which is bad too. Anybody cool with that one? More questions before I cut it off?