c -1: 2, 1: 2
c -2: 2, 2: 3
c -3: 2, 3: 4
c -4: 2, 4: 1
c -5: 3, 5: 2
c -6: 3, 6: 2
c -7: 2, 7: 3
c -8: 3, 8: 3
p cnf 8 13
4 -8 1 0
3 8 -5 0
-5 -8 -6 0
-2 7 -6 0
1 -3 -7 0
-3 -8 7 0
2 3 5 0
-6 3 8 0
2 -5 -7 0
8 -2 3 0
-1 -4 7 0
-1 5 6 0
2 6 -4 0