At the park there is a pool shaped like a circle. A ring-shaped path goes around the pool. Its inner diameter is 12 yd, and its outer diameter is 16 yd.

We are going to give a new layer of coating to the path. If one gallon of coating can cover 4 yd^2, how many gallons of coating do we need? Note that coating comes only by the gallon, so the number of gallons must be a whole number. (Use the value 3.14 for pi.)