c instance by G2
c no solution
p cnf 20 101
18 -8 17 0
14 17 -7 0
-17 -2 9 0
-7 14 -20 0
-4 -3 -9 0
6 1 10 0
-16 5 13 0
11 6 14 0
-5 17 -15 0
14 -8 9 0
3 -2 -15 0
19 -5 -8 0
-10 -1 -16 0
-8 2 1 0
-16 -12 8 0
-16 12 -9 0
12 -2 3 0
-12 8 -6 0
18 10 6 0
20 2 -14 0
-4 -6 -8 0
10 4 17 0
-9 1 -14 0
5 20 6 0
7 3 19 0
15 -6 -20 0
-17 -2 3 0
14 -6 -19 0
-13 8 -16 0
-8 -19 4 0
1 -17 -6 0
-6 -18 4 0
-11 -5 12 0
4 16 -12 0
-8 16 -14 0
20 14 4 0
-11 -1 -15 0
18 -16 -2 0
-12 8 -4 0
17 19 -5 0
-8 13 6 0
-17 -7 9 0
13 -6 4 0
6 -3 20 0
13 2 -18 0
11 14 -18 0
-3 11 -4 0
12 -15 -16 0
14 5 -16 0
9 14 20 0
-10 -14 2 0
11 18 16 0
-3 4 14 0
-13 6 15 0
-14 13 16 0
-2 10 7 0
-13 -11 3 0
-12 -18 1 0
-2 -12 -7 0
-12 14 6 0
12 -19 -20 0
-16 4 -5 0
-1 -15 -8 0
8 5 -16 0
19 -5 -20 0
-7 4 6 0
2 15 19 0
17 10 8 0
-1 -7 -19 0
-8 -17 2 0
14 3 16 0
4 3 -17 0
10 -12 3 0
19 14 2 0
7 -14 19 0
19 2 -8 0
-2 -18 -6 0
-5 1 -9 0
1 -12 10 0
3 -2 -12 0
-8 16 14 0
20 16 19 0
15 -4 -10 0
-19 -18 -15 0
-7 -8 15 0
-11 13 -2 0
5 -4 6 0
-9 18 -11 0
-8 18 -5 0
-2 4 -15 0
13 -18 -10 0
2 18 -4 0
-8 -2 -11 0
-13 -1 -5 0
-12 -8 -6 0
14 -13 -1 0
-11 -4 8 0
-7 -18 -19 0
12 -11 -3 0
-1 18 -13 0
-13 -15 -18 0
%