So in the first step, two molecules of acetylcoenzme A are combined to form acetoacetal coenzyme A. And this is a reversible reaction that is catalyzed by thylase. Now, in the next step, the next step is actually a rate determining step. And in fact, it's this step that drives this reaction forward. Because here we cleave a high energy thio etherbond via a hydrolysis reaction. So we use a water molecule and we also combine another CETL, coenzyme A.