defense establishment in general and the Air Force in particular, such as the mid and late 1970s following the end of the Vietnam War and associated USAF force structure reductions or the post-Cold War era and its associated defense reductions of the early and mid-1990s. During these periods of contractions, OTS produces few officers, making selection for the OTS program particularly difficult and competitive for college graduates, especially those with no prior enlisted service, particularly USAF enlisted service. Structure OTS is divided into three programs: Officer Training School (OTS) (formerly known as Basic Officer Training (BOT) and later, Total Force Officer Training (TFOT)) is the more traditional 8-week pre-commissioning program. Previously a 13-week program later reduced to 10 weeks, the renamed TFOT track transitioned to a 9-week program in 2014 and the legacy system of Officer Trainees (OT) being designated as lower classmen in the early part of the program and upper classmen in the latter part, similar to their USAFA and AFROTC counterparts, was eliminated. This was further reduced to the current 8-week program in 2017 by removing the Total Force Indoctrination Training (TFIT) from the first week of the course in which Military Training Instructors (MTIs) would teach the customs and standards of the Air Force as well as the basics of marching and drill and ceremonies. Officer Trainees were also re-designated as Cadets in 2015, again on par with USAFA and AFROTC and reminiscent of the Aviation Cadet program in operation in USAF and its predecessor incarnations (e.g., USAAS, USAAC, USAAF, etc.) from 1907 until 1965. As of 2019, the class is an 8-week program and students are once again referred to as Officer Trainees. OTS is for four-year university and college graduates without prior military service (commonly known as non-prior service), as well as Active Component enlisted, Air Force Reserve enlisted, Air National Guard enlisted and former enlisted personnel from any of the six U.S. armed services with college degrees at the baccalaureate level or higher who wish to become Air Force officers. OTS serves all Active Component and Reserve Component line officers except judge advocates. Officer Training School-Abbreviated (OTS-A) (formerly known as Commissioned Officer Training (COT)) is a five-week program primarily focused on terminal-degreed professionals (e.g., medical, lawyers, chaplains, as well as undergraduate degreed nurses) directly accessed into the USAF officer ranks. OTS-A serves all Regular Air Force, Air Force Reserve and Air National Guard