@Override
	public int hashCode() {
		final int prime = 31;
		int result = 1;
		result = prime * result + ((data == null) ? 0 : data.hashCode());
		result = prime * result + ((left == null) ? 0 : left.hashCode());
		result = prime * result + ((right == null) ? 0 : right.hashCode());
		return result;
	}