How many premolars are present in the dentition of an adult human?

An adult human has 32 permanent teeth which are of four different types namely, incisors (I), canine (C), premolars (PM) and molars (M). Arrangement of teeth in each half of the upper and lower jaw in the order I, C, PM, M is represented by a dental formula which in human is  21232123. There are two premolars per quadrant in the permanent set of teeth, making a total of eight premolars.