private LinkedList<Fraction> mergeList(LinkedList<Fraction> list1,
			LinkedList<Fraction> list2){
		LinkedList<Fraction> list=new LinkedList<Fraction>();
		int cmp=0;
		
		while(!list1.isEmpty() && !list2.isEmpty()){
			cmp=COMPARATOR.compare(list1.peek(), list2.peek());
			if(cmp<=0){
				list.add(list1.removeFirst());
			}else{
				list.add(list2.removeFirst());
			}
		}
		if(!list1.isEmpty()){
			list.addAll(list1);
		}
			
		if(!list2.isEmpty()){
			list.addAll(list2);
		}
		return list;
	}