有n个长方形盒子，第i个长度为Li，宽度为Wi，我们需要把他们套放。注意一个盒子只可以套入长和宽分别不小于它的盒子，并且一个盒子里最多只能直接装入另外一个盒子 （但是可以不断嵌套），例如1 * 1 可以套入2 * 1，而2 * 1再套入2 * 2。套入之后盒子占地面积是最外面盒子的占地面积。给定N个盒子大小，求最终最小的总占地面积。-There are n rectangular boxes, the length of the Li is I, and the width is Wi, we need to put them on the set. Note that a box can only be set in length and width, respectively, not less than the box, and a box can only be directly loaded into another box (but can be nested), such as 1* 1 can be set to 2* 1, while 2* 1 and then set to 2* 2. Cover after the box covers an area of the most out of the box area. Given the size of the N box, the total floor area of the final minimum.