4589: P1183 多边形的面积

Memory Limit:128 MB Time Limit:1.000 S
Judge Style:Text Compare Creator:
Submit:0 Solved:0

Description

Input

Output

Sample Input Copy

10
0 0
4 0
4 1
3 1
3 3
2 3
2 2
1 2
1 3
0 3

Sample Output Copy

9

HINT