South Korean President Moon Jae-in (front C) walks with Kim Yong Nam (front L), president of the Presidium of the Supreme People's Assembly of the Democratic People's Republic of Korea (DPRK), and Kim Yo Jong (front R), the younger sister of top DPRK leader Kim Jong Un, at the Blue House in Seoul, capital of South Korea, on Feb. 10, 2018. (Xinhua/Newsis)