A ring of radius $R$ is rolling purely on the outer surface of a fixed pipe of radius $4R$.  At some instant, the centre of the ring has a constant speed $v$ as shown in fig. Then, the acceleration of the point ‘B’ on the ring w.r.t. ground which is in contact with the surface of the pipe is $\frac{x{\upsilon }^2}{yR}$. The value of $x+y$ is [$x$ & $y$ are least possible integers]