 Okay, so what type is this one? It's a propagation. How do you know that? So you use the propagation. Why? Because we've got the one radical here and this thing is one radical. What is this? Yeah, this is in addition to the pi bond, right? What's happening? So this is a type of propagation or a kind of propagation stem and it's called addition. So again, it's a propagation radical stem because it's one radical to one radical. Any questions?