S.D. Codified Laws § 49-30-14

In the election of directors each stockholder shall be entitled to one vote, either in person or by proxy, for every share of stock owned by him for thirty days next preceding such election. Vacancies shall be filled in the manner prescribed in the bylaws. Inspectors of the first election of directors shall be appointed by the board of directors named in the articles of incorporation, and thereafter as provided by the bylaws.