c  ----------- DIMACS Challenge - CNF format -----------
c
c  TRISAT Generator (Pretolani 1990)
c
c                  (Even) number of nodes ==>    6
c        Charge ( 0 = sat. / 1 = unsat. ) ==>    1
c  Horn Percentage (min -> 25; max -> 75) ==>   75
c      Number of  Propositional variables ==>    9
c                       Number of Clauses ==>   24
c                   Nodes with Charge = 1 ==>    5
c                 Horn Percentage (exact) ==> 50.000
c
c  -----------------------------------------------------
p cnf    9   24
     -3      -2      -1 0
      3       2      -1 0
      2       1      -3 0
      3       1      -2 0
      5       4       1 0
      5      -4      -1 0
      4      -5      -1 0
      1      -5      -4 0
      7       6       4 0
      7      -6      -4 0
      6      -7      -4 0
      4      -7      -6 0
      8       6       5 0
      8      -6      -5 0
      6      -8      -5 0
      5      -8      -6 0
      9       7       3 0
      9      -7      -3 0
      7      -9      -3 0
      3      -9      -7 0
      9       8       2 0
      9      -8      -2 0
      8      -9      -2 0
      2      -9      -8 0
0