public static LinkedList<Integer> sum(LinkedList<Integer> op1, LinkedList<Integer> op2) {

		// Lista rezultanta
		LinkedList<Integer> resultList = new LinkedList<Integer>();
		// Iteratorii listelor
		ListIterator<Integer> it1 = op1.listIterator(op1.size());
		ListIterator<Integer> it2 = op2.listIterator(op2.size());

		Integer sum = 0;
		Integer coada = 0;
		while (it1.hasPrevious() && it2.hasPrevious()) {
			sum = it1.previous() + it2.previous() + coada;
			if (sum > 0) {
				resultList.add(sum % 10);
				coada = 1;
			} else {
				resultList.add(sum);
				coada = 0;
			}
		}

		if (it1.hasPrevious() || it2.hasPrevious()) {
			Integer aux = 0;
			if (it1.hasPrevious() && it2.hasPrevious()) {
				aux = it1.previous() + it2.previous();
			} else {
				aux = it1.hasPrevious() ? it1.previous() : it2.previous();
			}
			sum = aux;
			if (sum > 0) {
				resultList.add(sum % 10);
				coada = 1;
			} else {
				resultList.add(sum);
				coada = 0;
			}
		}


		Collections.reverse(resultList);

		return resultList;
	}