12
-1 1 -1 5
0 2 -4 2
1 2 5 2
2 0 2 -4
-1 0 -1 -4
2 1 2 5
-1 3 3 -1
0 -1 -4 -1
1 -1 5 -1
-2 2 2 -2
-1 -2 3 2
-2 -1 2 3