SDCL § 12-22-16: Answer to present all defenses--Admission of matters not denied--Affirmative defense.

No pleading to the complaint, other than an answer, shall be permitted, and all defenses of fact or law must be presented in such answer. Any matters alleged in the complaint and not denied shall be deemed admitted, but the court may, in its discretion, require that such admitted matters be nevertheless shown by competent evidence. The answer may also set forth matter in the nature of an affirmative defense.