//
// How many dominos are there?
// Expressed as a CP 
//
// Can we prove this is correct using a counting argument?
//

import choco.Problem;
import choco.ContradictionException;
import choco.integer.*;
import choco.Solver;
import choco.Solution;

public class Domino {

  
  public static void main(String[] args) {
     Problem pb = new Problem();
     IntDomainVar v1  = pb.makeEnumIntVar("v1",0,6);
     IntDomainVar v2  = pb.makeEnumIntVar("v2",0,6);
 
     pb.post(pb.leq(v1,v2));

     
     if (pb.solve().booleanValue()){
	 System.out.println("[" + v1.getVal() + " : " + v2.getVal() + "]");
	 //System.out.println(pb.pretty());
	while (pb.nextSolution().booleanValue()) 
	    System.out.println("[" + v1.getVal() + " : " + v2.getVal() + "]");
	//System.out.println(pb.pretty());
     }
     	
     /*
     Solver s = pb.getSolver();
     pb.solve(true);
     System.out.println("feasible: " + pb.isFeasible());
     System.out.println("nbSol: " + s.getNbSolutions());
     */
  }
}