p cnf 10 20
-5 1 0
-5 2 0
-1 -2 5 0
-6 3 0
-6 4 0
-3 -4 6 0
-7 5 0
-7 6 0
-5 -6 7 0
-8 1 0
-8 2 0
-1 -2 8 0
-9 3 0
-9 4 0
-3 -4 9 0
-10 8 0
-10 9 0
-8 -9 10 0
7 10 0
-7 -10 0