Why the first three? Well, because the first three are basically used to form that acetyl coenzyme A complex. So in the first step, we have a decrypt oxylation reaction taking place in which this entire component, not including these two electrons in this bond, is basically removed because we want to form the carbon dioxide and we form this intermediate. Now, remember, decorboxylation reactions like the one shown here are generally exergonic reactions. They release energy, and that free energy that is released in the decarboxylation process is used to power the other reactions that are endergonic in this particular process. So once we form this intermediate, the two electrons are then abstracted.