The affairs of each association shall be managed by not less than five directors, who shall be elected by the shareholders at a meeting to be held at any time before the association is authorized by the Comptroller of the Currency to commence the business of banking; and afterward at meetings to be held on such day of each year as is specified therefor in the bylaws. The directors shall hold office for a period of not more than 3 years, and until their successors are elected and have qualified. In accordance with regulations issued by the Comptroller of the Currency, a national bank may adopt bylaws that provide for staggering the terms of its directors.