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Let the point \((p, p+1)\) lie inside the region \(E=\left\{(x, y): 3-x \leq y \leq \sqrt{9-x^{2}}, 0 \leq x \leq 3\right\}\). If the set of all values of \(\mathrm{p}\) is the interval \((a, b)\), then \(b^{2}+b-a^{2}\) is equal to ___________.