16
-2 2 -2 3
-2 3 -1 3
-1 3 -1 4
-1 4 0 4
0 4 0 5
0 5 1 5
1 5 1 0
1 0 0 0
0 0 0 4
0 4 2 4
2 4 2 1
2 1 -1 1
-1 1 -1 3
-1 3 3 3
3 3 3 2
3 2 -2 2