Description

Input Format

The first line contains a positive integer $n\ (3 \le n \le 1500)$, denoting the number of vertices of the polygon. Then $n$ lines follow, each containing two integers $x_i,y_i\ (-500 \le x_i,y_i \le 500)$, representing the coordinates of the polygon’s vertices in order.

Output Format

Output the area of the shaded region, rounded to $2$ decimal places.

5									
0 0
0 6
6 6
6 0
3 3

9.00

Hint

Translated by ChatGPT 5