Ministry of Defence, the General Staff, branches of the Armed Forces, executive system and a training system of the Armed Forces were established in this short span of time. After some time, it became apparent that the process of the Armed Forces improvement had just begun. And the problem was that not only there were no special system and efficient plan for resolving the military development problems of that time, but also that it was lack of trained personnel for its development and realization. A shuffle in the military department's administration had a rather negative effect on the process of military development. From 1991 till 1996, three Ministers of Defence and four Chiefs of General Staff were changed. About 70% of administrative staff was changed in the early stages of forming the Armed Forces of Ukraine. All military district commanders, army commanders, corps and division commanders were changed several times over. This problem was complicated by the countries instability, connected with international dislocation of military personnel. About 12000 officers pledged their allegiance to other countries (Mostly Russia) and more than 33000 personnel came back to serve the Ukrainian army between 1991 till 1994. No doubt, that the main reason of dissatisfied realization of the main procedures of the Armed Forces development process was permanent reduction of common part of expenses for National Defence at all; expenses for the Armed Forces, purchases of armament and military vehicles, providing the research engineering and design efforts. The progress of Ukraine's military organization and development are (by the Ministry of Defence) divided into three main periods:  The aspects of the first period of development were the forming the legal foundation of the Armed Forces activity, reorganization of its structure, establishment of the corresponding executive structures and supporting structures, and other elements, which were necessary for its functioning. The first stages of development of the Armed Forces also began the reduction of the military institutions, number of personnel, and number of armament and nuclear technology. As such a large quantity of weaponry was both unnecessary for Ukraine and could not have been maintained with the provided defence budget. At the end of 1996, more than 3500 different military institutions and 410000 personnel were discharged. Also, the number of armament and defence technologies was decreased: combat aircraft – by 600 units, helicopters – by 250, the garrison tanks and combat armed vehicles by 2400 and 2000. Throughout the 1992–1997 the army was reduced by 400,000 servicemen. More than 1300 units, organizations, command and control installations were disbanded during that period. By the end of 1999 the organizational strength of the Armed Forces is to number around 400,000 men, including 310,000 military and 90,000 civilians.