输入描述:

The first line contains an integer  — the number of vertices of the polygon.
Then  lines follow. The -th line contains two integer  — the coordinates of the -th
polygon vertex. The vertices are given in clockwise order, and no three consecutive vertices are collinear.
The next line contains an integer  — the number of cameras.
Then  lines follow. The -th line contains two integer  — the coordinate of the -th
camera.
It is guaranteed that the cameras are strictly inside the gallery.

输出描述:

Output the area of the monitored points. Your answer should have an absolute or relative error less
than 
. Namely, if your answer is  and the jury’s answer is , then your answer is accepted if
.

8
0 0
0 5
5 5
5 10
10 10
10 5
50 5
50 0
1
8 7

79.166666667