c status 20
c --probeinit=0
p cnf 14 15
-7 -2 8 6 0
-5 4 0
8 -10 0
13 7 0
-11 9 0
-8 -9 12 0
-6 10 0
-13 8 0
14 -1 0
5 1 0
5 -14 0
-12 -3 0
2 -4 0
-5 11 0
3 -4 0