Cosine Chain

Geometry Level 2

$\large\cos\left(\dfrac{2\pi}{15}\right)\cos\left(\dfrac{4\pi}{15}\right)\cos\left(\dfrac{8\pi}{15}\right)\cos\left(\dfrac{14\pi}{15}\right)=\dfrac{A}{B}$

If $A,B$ are co-prime integers , find $B - A$ .