SEOUL: South Korean President Moon Jae-in sat next to the powerful sister of the North´s leader Kim Jong Un at a concert in Seoul by musicians from Pyongyang, as conservative protesters burned the North´s national flag outside Sunday.The show was the final set-piece element of the North Korean delegation´s landmark visit, the diplomatic highlight of the Olympics-driven rapprochement between the two halves of the peninsula, and they flew back home afterwards. They have shared kimchi and soju with Moon, sat in the same box at the Olympics opening ceremony and cheered a unified women´s ice hockey team together. Kim on Saturday invited Moon to a summit in the North, an offer extended by his sister and special envoy Kim Yo Jong.