12
0.0 0.0
1.0 2.0
2.0 1.0
3.0 3.0
4.0 0.0
5.0 2.0
6.0 1.0
7.0 3.0
8.0 0.0
2.5 -1.0
4.5 -1.5
6.5 -0.5