Question: Information:  - Hongik University, widely known as the best architecture and art institution rivalry with Seoul National University (SNU) in South Korea, is a university in the Mapo-gu district of central Seoul, South Korea with a second campus in Sejong. Hongik University offers a comprehensive range of undergraduate and graduate programs. As of 2007, 14,500 undergraduate students and 2,600 graduate students were enrolled at the university. The university serves as a metonym for the Hongdae area, which was named one of the coolest neighborhoods in the world in 2016.  - Seoul Subway Line 2 (dubbed "The Circle Line") is a circular line of the Seoul Metropolitan Subway. The line running clockwise is called the "inner circle line" and the counter-clockwise line is called the "outer circle line". This is Seoul's most heavily used line, and consists of the main loop (47.7 km), the Seongsu Branch (5.4 km) and the Sinjeong Branch (6.0 km) for a total line length of 60.2 km. The Line 2 loop is the second longest subway loop in the world after Beijing Subway Line 10.  - Hongik University Station is a station on the Seoul Subway Line 2 as well as the AREX and Yongsan lines. As its name indicates, it serves the nearby Hongik University. It was formerly known as Donggyo Station, after the neighborhood that it serves.  - Sangsu Station is a subway station on the Seoul Subway Line 6 . Along with Hongik University Station on Line 2 , it serves the area commonly called Hongdae , albeit geographically less convenient .    Given the paragraphs above, decide what entity has the relation 'country' with 'south korea'.
Answer:
sangsu station