Parabola Part 2

Let A and B be the points of intersection of the line y+5=0 and the mirror image of the parabola y2=4x with respect to the line x+y+4=0. If d denotes the distance between A and B, and a denotes the area of △SAB, where S is the focus of the parabola y2=4x, then the value of (a+d) is ______