30-13

0 0
1 -1
-1 0
0 1
0 -1
-1 2
-1 1
-2 3
2 -1
3 -1
-3 3
-2 1
-2 0
-3 1
0 2
-4 3
-3 0
0 3
2 0
3 -2
-4 1
-5 3
-6 3
-5 4
-2 4
1 2
2 1
-6 2
-1 -1
-4 2