Input Format

• Variables given numbers from 1 to n.
• Variable negation shown by negating the variable number.
• Lines are zero terminated (not for tableau, unfortunately).
• Comment lines begin with `c'.
• First content line has ``p cnf n m'' where n is the number of variables and m the number of clauses.
• After that, it's one clause per line.

Example:

c generated by makewff, seed= 702008999
p cnf 4 8
1 -2 -4 0
1 -2 4 0
1 2 -3 0
1 2 3 0
-1 -2 3 0
-1 -3 4 0
-1 2 -4 0
-2 -3 -4 0