The Full form of NDA is National Defence Academy. The National Defence Academy exam is conducted by the Union Public Service Commission (UPSC) for the recruitment of candidates to Army, Navy and Air Force wings of the National Defence Academy. NDA is a Joint Services academy of the Indian Armed Forces, where cadets of the three services, the Army, the Navy and the Air Force are trained together before they go on to pre-commissioning training to their respective service academies. The National Defence Academy entrance exam is held twice a year, generally in the month of April and September. The National Defence Academy is located in Khadakwasla near Pune (Maharashtra). NDA is the first tri-service academy in the world. NDA has produced a lot of officers for the Indian Armed Forces. It has produced 27 service chiefs till date including 3 Param vir chakra and 9 Ashok chakra recipients. The educational qualification for Indian Army wing of National Defence Academy is; the candidate must have passed or appeared for class 12th exam from a recognized board or university and for Air force and Indian Navy; the candidate must have passed or appeared for class 12th with physics and Mathematics as main subjects from a recognized board or university.