class SLLNode<E extends Comparable<E>> {
	protected E element;
	protected SLLNode<E> succ;

	public SLLNode(E elem, SLLNode<E> succ) {
		this.element = elem;
		this.succ = succ;
	}

	@Override
	public String toString() {
		return element.toString();
	}
}

class SLL<E extends Comparable<E>> {
	private SLLNode<E> first;

	public SLL() {
		// Construct an empty SLL
		this.first = null;
	}

	public void deleteList() {
		first = null;
	}

	public int length() {
		int ret;
		if (first != null) {
			SLLNode<E> tmp = first;
			ret = 1;
			while (tmp.succ != null) {
				tmp = tmp.succ;
				ret++;
			}
			return ret;
		} else
			return 0;

	}

	@Override
	public String toString() {
		String ret = new String();
		if (first != null) {
			SLLNode<E> tmp = first;
			ret += tmp + "->";
			while (tmp.succ != null) {
				tmp = tmp.succ;
				ret += tmp + "->";
			}
		} else
			ret = "Prazna lista!!!";
		return ret;
	}

	public void insertFirst(E o) {
		SLLNode<E> ins = new SLLNode<E>(o, first);
		first = ins;
	}

	public void insertAfter(E o, SLLNode<E> node) {
		if (node != null) {
			SLLNode<E> ins = new SLLNode<E>(o, node.succ);
			node.succ = ins;
		} else {
			System.out.println("Dadenot jazol e null");
		}
	}

	public void insertBefore(E o, SLLNode<E> before) {

		if (first != null) {
			SLLNode<E> tmp = first;
			if (first == before) {
				this.insertFirst(o);
				return;
			}
			// ako first!=before
			while (tmp.succ != before)
				tmp = tmp.succ;
			if (tmp.succ == before) {
				SLLNode<E> ins = new SLLNode<E>(o, before);
				tmp.succ = ins;
			} else {
				System.out.println("Elementot ne postoi vo listata");
			}
		} else {
			System.out.println("Listata e prazna");
		}
	}

	public void insertLast(E o) {
		if (first != null) {
			SLLNode<E> tmp = first;
			while (tmp.succ != null)
				tmp = tmp.succ;
			SLLNode<E> ins = new SLLNode<E>(o, null);
			tmp.succ = ins;
		} else {
			insertFirst(o);
		}
	}

	public SLLNode<E> getFirst() {
		return first;
	}

	public Iterator<E> iterator() {
		// Return an iterator that visits all elements of this list, in
		// left-to-right order.
		return new LRIterator<E>();
	}

	// //////////Inner class ////////////

	private class LRIterator<E extends Comparable<E>> implements Iterator<E> {

		private SLLNode<E> place;

		@SuppressWarnings("unchecked")
		private LRIterator() {
			place = (SLLNode<E>) first;
		}

		public boolean hasNext() {
			return (place != null);
		}

		public E next() {
			if (place == null)
				throw new NoSuchElementException();
			E nextElem = place.element;
			place = place.succ;
			return nextElem;
		}

		public void remove() {
			// Not implemented
		}
	}