Vietnam's President Truong Tan Sang (C) walks between Prime Minister Nguyen Tan Dung (front), Hanoi City's Party Chief Pham Quang Nghi (L top) and Defence Minister Phung Quang Thanh (R, top) at the opening ceremony of the 12th National Congress of Vietnam's Communist Party in Hanoi, Vietnam, January 21, 2016. REUTERS/Kham