两个矩形，告诉你矩形1，矩形2的面积和他们的总面积，请你求两矩形重叠部分的面积。如果给你的情况不存在，就输出Impossible。-Two rectangles, to tell you a rectangle, rectangular area and two of their total area, please seek two rectangles overlap area. If you give your situation does not exist, the output Im