c instance by G2
c 
p cnf 27 135
6 23 5 0
-7 -20 -23 0
17 -22 9 0
-10 2 -1 0
-12 -19 2 0
3 19 -22 0
22 6 -18 0
12 -11 5 0
2 9 6 0
23 21 -1 0
14 -18 -5 0
-15 -3 7 0
20 -17 14 0
-12 -18 24 0
-12 -16 -19 0
6 -18 -4 0
-27 -22 -10 0
-11 -22 -9 0
-2 12 18 0
-21 -19 -24 0
8 -10 24 0
25 -14 -17 0
2 -17 -19 0
-20 -10 11 0
13 -5 4 0
24 -17 15 0
-4 -26 -13 0
6 20 11 0
21 -5 -6 0
-5 12 6 0
8 -9 -5 0
3 24 -14 0
23 -5 -9 0
15 2 -27 0
-19 21 -14 0
-21 -27 -18 0
-21 17 -24 0
2 1 10 0
10 -25 6 0
-8 -20 22 0
-6 -23 13 0
-25 -17 -5 0
-2 19 -21 0
11 6 -14 0
-17 13 -3 0
15 -12 -10 0
-1 -11 22 0
-10 -20 -7 0
23 -5 -7 0
25 22 -14 0
3 2 26 0
-3 -11 26 0
-1 14 19 0
-26 5 -25 0
21 20 -12 0
-13 5 6 0
-12 -17 23 0
24 -27 19 0
-1 -17 19 0
19 -6 4 0
25 4 9 0
-11 25 -6 0
19 17 -22 0
25 -2 -17 0
-5 -27 -15 0
3 20 -23 0
-24 19 -22 0
8 -13 18 0
-26 -5 24 0
22 -27 -17 0
15 -25 -19 0
7 -12 -27 0
13 17 20 0
1 -13 27 0
-27 9 5 0
17 -26 13 0
10 -27 14 0
-15 -8 3 0
-20 14 1 0
24 -13 -18 0
-7 1 -19 0
19 11 -14 0
-18 -11 16 0
11 12 -20 0
18 -7 13 0
7 -26 23 0
2 25 -17 0
-18 15 -25 0
21 -2 -26 0
-1 24 -5 0
26 27 4 0
-24 -21 20 0
2 15 17 0
6 25 -7 0
27 -22 15 0
27 12 14 0
-10 -7 -4 0
9 -26 -13 0
11 13 21 0
-14 -1 19 0
-19 -4 12 0
-19 5 -21 0
-24 -21 -2 0
-3 12 -5 0
-3 -16 21 0
-21 22 -2 0
-10 -17 19 0
18 -8 5 0
-12 26 -3 0
-3 -15 -11 0
-16 3 22 0
8 -7 -15 0
-3 -6 -23 0
-22 -21 8 0
-8 -13 -5 0
5 -13 -2 0
-9 -8 22 0
-9 23 12 0
10 13 -8 0
-11 -13 6 0
23 -18 -26 0
-16 -7 23 0
9 -21 -16 0
-24 9 -16 0
-12 -11 25 0
2 16 -15 0
-4 26 22 0
-17 4 9 0
25 -19 3 0
-3 14 -24 0
17 13 26 0
-5 26 -27 0
-10 27 25 0
1 21 -8 0
-21 6 3 0