So we have molecule one, molecule two, molecule three, molecule four, molecule five, and molecule six. So let's suppose that each one of these molecules carries the same amount of energy, and each energy is equal to one unit. So we have six molecules. So we have, let's say, six units of energy on this side. Now, what about the amount of energy on this side? Well, we have no molecules on this side, so we have zero units of energy.