Let \(P(\frac{2√3}{√7} ,\frac{ 6}{√7} ), \)Q,R and S be four points on the ellipse 9x2 + 4y2 = 36. Let PQ and RS be mutually perpendicular and pass through the origin. If \(\frac{1}{( P Q ) ^2} + \frac{1}{( R S ) ^2} = \frac{P}{q }\), where p and q are coprime, then p + q is equal to