class CustomList{
	TreeSet indexes;
	HahMap items;
	int maxSize = 0;
	int realSize = 0;
	add(Object item) {
		int curItemIndex = maxSize++;
		realSize ++;
		indexes.add(curItemIndex);
		items.put(curItemIndex, item);
	}
	remove(int index) {
		int realIndex = indexes.rank(index);
		realSize--;
		indexes.remove(realIndex)
		item.remove(realIndex);
	}




}