We have the gamma shown in red. We have the epsilon shown in blue and we have the delta shown in purple here. Now let's discuss this alpha and the beta. We actually have three individual alpha units and three individual beta units. And these three alpha and three beta units basically create this hexameric alpha three beta three ring structure as shown in the following diagram. So these alpha and beta units basically alternate to form this ring structure that consists of these six individual polypeptide chains.