20
2 -4 2 0
2 1 2 5
-4 -1 0 -1
1 -1 5 -1
-4 2 0 2
1 2 5 2
1 -4 5 0
1 5 5 1
-1 3 3 -1
-4 0 0 -4
-1 -1 3 3
-1 -2 3 2
-1 2 3 -2
0 -1 0 3
-1 3 3 3
1 1 1 5
0 3 4 -1
1 0 5 0
3 -1 3 3
0 1 4 1