So, again, very important step because it allows us to drive the equilibrium of this reaction toward the product side. So ultimately, it's the indirect action of ATP that sets up this reaction and allows us to undergo this decarboxylation step that drives this reaction forward. Now, let's move on to step number five. So in step number five, this acetoacetal group is our reactant molecule. Now, this step number five is a reduction step. And the reductant molecule that we use is NADPH.