The Russian Armed Forces are divided into the Ground Forces, the Navy, and the Aerospace Forces—and there are also two independent arms of service: the Strategic Missile Troops and the Airborne Troops. , the military had around one million active-duty personnel, which is the world's fourth-largest. Additionally, there are over 2.5 million reservists, with the total number of reserve troops possibly being as high as 20 million. It is mandatory for all male citizens aged 18–27 to be drafted for a year of service in Armed Forces.