public void addNode (int coefficient, int exponent) {
			if (head == null) {
				head = new Node(coefficient, exponent);
				return;
			}

			if (head.exponent < exponent) {
				Node added = new Node(coefficient, exponent);
				added.next = head;
				head = added;
				return;
			} else if (head.exponent == exponent) {
				head.coefficient += coefficient;
				return;
			}

			Node current = head;
			while (current.next != null) {
				if (current.next.exponent > exponent) {
					current = current.next;
				} else if (current.next.exponent < exponent) {
					Node added = new Node(coefficient, exponent);
					added.next = current.next;
					current.next = added;
					return ;
				} else {
					current.next.coefficient += coefficient;
					return ;
				}
			}
			current.next = new Node(coefficient, exponent);
		}