ACP (the Arc Consistency program) can be used as a first step in solving
Constraint Satisfaction problems. It eliminates impossible values from domains
of variables, by repeatedly applying constraints defined on pairs of variables.

The program takes one argument: an input file.
This input file contains
- the number of variables
- the number of possible values
- the number of connections
- the number of relations
- the number of relationpairs
- the seed for the random number generator.
