@Override
	public int compareTo(Constraint o) {
		 if (this.name == o.name)
	            return 0;
	        else if (this.name.startsWith("S") &&  o.name.startsWith("Z"))
	            return 1;
	        else if (this.name.startsWith("Z") &&  o.name.startsWith("C"))
	        	return -1;
	        else if (Integer.parseInt(this.name.substring(1)) > Integer.parseInt(o.name.substring(1)))
		 		return 1;
	        else
	            return -1;
	    }