In the given figure, the area of the shaded portion is \( \left(\pi-\frac{\sqrt{3}}{2}\right) R^{2} \), \( v \) \( R \) is the radius of the circle with \( C \) O. If \( B C>A B, A B \perp B C \), then the v of \( \left(\frac{2}{3} \angle B A C+\frac{5}{2} \angle A C B\right) \) will be