Let y = f \left(\right. x \left.\right) be a thrice differentiable function in \left(\right. - 5 , 5 \left.\right). Let the tangents to the curve y = f \left(\right. x \left.\right) at \left(\right. 1 , f \left(\right. 1 \left.\right) \left.\right) and \left(\right. 3 , f \left(\right. 3 \left.\right) \left.\right) make angles \pi / 6 and \pi / 4, respectively with positive x-axis. If 27 \int_{1}^{3} \left(\right. \left(\left(\right. f^{′} \left(\right. t \left.\right) \left.\right)\right)^{2} + 1 \left.\right) f^{′ ′} \left(\right. t \left.\right) d t = \alpha + \beta \sqrt{3} where \alpha , \beta are integers, then the value of \alpha + \beta equals