BOSTON — A U.S. military veteran who lost both legs in Afghanistan is running 31 marathons in 31 cities — in 31 days.Now-retired U.S. Marine Corps Sgt. Rob Jones kicked off his odyssey in London last week. He's scheduled to run 26.2 miles (42.2 kilometers) around Boston's Castle Island on Sunday — his fourth of 31 consecutive attempts to cover the classic marathon distance.Jones grew up in Lovettsville, Virginia.