In the Dark Forest, the territory you control is defined by the smallest convex polygon that contains all trees you control. Your power is defined by the area of the territory you control.

You currently control out of trees in the Dark Forest. What is the highest power you can achieve by gaining control over a single additional tree somewhere in the forest?

输入描述:

The first line of input consists of two space-separated integers  and  .
Next follow  lines each with two space-separated integers  and   specifying the locations of the  trees. You control the first  trees given in the list; the other  trees do not
belong to you. (Note that some of these may still be inside your territory.)
It is guaranteed that no three trees have collinear locations.

输出描述:

Print, on a single line, the maximum power you can achieve by gaining control over a singleadditional tree. The output should be rounded and displayed to exactly one decimal place. 

5 3
-5 -5
-5 5
5 -5
-4 6
5 5

100.0

4 3
999999999 999999999
999999998 -1000000000
-999999999 999999998
-1000000000 -999999999

3999999992000000004.0

10 9
4 3
3 8
7 9
8 1
9 9
1 0
9 2
10 4
5 3
7 1

58.5