c an ALC problem
p cnf 10 13
-1 2 -3 0
-1 2 -4 0
-5 6 -3 0
-5 6 -4 0
-1 2 7 0
-5 6 7 0
-1 2 8 0
-5 6 9 0
10 0
1 0
5 0
-6 0
3 -7 0