Question: Information:  - The Rajang River is a river in Sarawak, Malaysia. The river is located in northwest of Borneo and it originates in the Iran Mountains. The river flows approximately 563 km into Kapit, and then to the South China Sea, making it the longest river in Malaysia.  - The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing an area from the Karimata and Malacca Straits to the Strait of Taiwan of around . The area's importance largely results from one-third of the world's shipping sailing through its waters and that it is believed to hold huge oil and gas reserves beneath its seabed.  - Vietnam, officially the Socialist Republic of Vietnam (SRV), is the easternmost country on the Indochina Peninsula in Southeast Asia. With an estimated 90.5 million inhabitants , it is the world's 14th-most-populous country, and the eighth-most-populous Asian country. Vietnam is bordered by China to the north, Laos to the northwest, Cambodia to the southwest, Thailand across the Gulf of Thailand to the southwest, and the Philippines, Malaysia and Indonesia across the South China Sea to the east and southeast. Its capital city has been Hanoi since the reunification of North and South Vietnam in 1976.  - The Bakun Dam is an embankment dam located in Sarawak, Malaysia, on the Balui River, a tributary or source of the Rajang River and some sixty kilometres west of Belaga. As part of the project, the second tallest concrete-faced rockfill dam in the world would be built. It is planned to generate 2,400 megawatts (MW) of electricity once completed.  - Sabah, nicknamed "Negeri Di Bawah Bayu" ("Land Below the Wind"), is one of the two Malaysian states on the island of Borneo (Sarawak being the other state). This territory has a certain level of autonomy in administration, immigration, and judiciary which differentiates it from the Malaysian Peninsula states. Sabah is situated in northern Borneo, bordering the state of Sarawak to the southwest, Kalimantan to the south, while separated by sea from the Federal Territory of Labuan in the west and the Philippines to the north and east. Kota Kinabalu is the capital city as well the economic centre for the state and the seat for the Sabah state government. Other major towns in Sabah include Sandakan and Tawau. As of the 2015 census in Malaysia, the state's population is 3,543,500. Sabah has an equatorial climate with tropical rainforests and abundant animal and plant species. The state has a long mountain ranges in the west side which formed as part of the Crocker Range National Park. Kinabatangan River is the second longest river in Malaysia while Mount Kinabalu is the highest point of Sabah as well for Malaysia.  - The Philippines, officially the Republic of the Philippines, is a sovereign island country in Southeast Asia situated in the western Pacific Ocean. It consists of about 7,641 islands that are categorized broadly under three main geographical divisions from north to south: Luzon, Visayas, and Mindanao. The capital city of the Philippines is Manila and the most populous city is Quezon City, both part of Metro Manila. Bounded by the South China Sea on the west, the Philippine Sea on the east and the Celebes Sea on the southwest, the Philippines shares maritime borders with Taiwan to the north, Vietnam to the west, Palau to the east and Malaysia and Indonesia to the south.  - Sibu is an inland town at the central region of Sarawak and the capital of Sibu District in Sibu Division, Sarawak, Malaysia. The town is located on the island of Borneo. The town covers an area of . It is located at the confluence of the Rajang and Igan Rivers, some 60 kilometres from the South China Sea and approximately north-east of the state capital Kuching. The population is mainly dominated by Chinese especially the Fuzhou people. Other ethnic groups such as indigenous Melanau, Malay, and Iban are also present in this region. The town population as of the year 2010 is 162,676.  - Brunei, officially the Nation of Brunei, the Abode of Peace (Jawi: ), is a sovereign state located on the north coast of the island of Borneo in Southeast Asia. Apart from its coastline with the South China Sea, the country is completely surrounded by the state of Sarawak, Malaysia. It is separated into two parts by the Sarawak district of Limbang. Brunei is the only sovereign state completely on the island of Borneo; the remainder of the island's territory is divided between the nations of Malaysia and Indonesia. Brunei's population was 408,786 in July 2012.  - Eurasia is the combined continental landmass of Europe and Asia. The term is a portmanteau of its constituent continents. Located primarily in the Northern and Eastern Hemispheres, it is bordered by the Atlantic Ocean to the west, the Pacific Ocean to the east, the Arctic Ocean to the north, and by Africa, the Mediterranean Sea, and the Indian Ocean to the south. The division between Europe and Asia as two different continents is a historical and cultural construct, with no clear physical separation between them; thus, in some parts of the world, Eurasia is recognized as the largest of five or six continents. In geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on the paleomagnet data.  - Balui River is a river in Sarawak, Malaysia. It is a tributary of the Rajang River. The 2400 megawatt Bakun hydroelectric dam is located on the river.  - A cave is a hollow place in the ground, specifically a natural underground space large enough for a human to enter. Caves form naturally by the weathering of rock and often extend deep underground. The word "cave" can also refer to much smaller openings such as sea caves, rock shelters, and grottos. A cavern is a specific type of cave, naturally formed in soluble rock with the ability to grow speleothems.  - Tin is a chemical element with the symbol Sn (for ) and atomic number 50, is a post-transition metal in group 14 of the periodic table. It is obtained chiefly from the mineral cassiterite, which contains tin dioxide, SnO. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundant element and has, with 10 stable isotopes, the largest number of stable isotopes in the periodic table, thanks to its magic number of protons. It has two main allotropes: at room temperature, the stable allotrope is -tin, a silvery-white, malleable metal, but at low temperatures it transforms into the less dense grey -tin, which has the diamond cubic structure. Metallic tin is not easily oxidized in air.  - Sarawak is one of the two Malaysian states on the island of Borneo (Sabah being the other state). This territory has a certain level of autonomy in administration, immigration, and judiciary. Sarawak is in northwest Borneo, bordering the state of Sabah to the northeast, Kalimantan, the Indonesian portion of Borneo, to the south, and the independent state of Brunei in the northwest. The capital city, Kuching, is the economic centre of the state and the seat of the Sarawak state government. Other cities and towns in Sarawak include Miri, Sibu, and Bintulu. As of the 2015 census in Malaysia, the total population of Sarawak is 2,636,000. Sarawak has an equatorial climate with tropical rainforests and abundant animal and plant species. It has several prominent cave systems at Gunung Mulu National Park. Rajang River is the longest river in Malaysia; Bakun Dam, one of the largest dams in Southeast Asia, is located on one of its tributaries, the Balui River. Mount Murud is the highest point in Sarawak.  - Singapore, officially the Republic of Singapore, and often referred to as the "Lion City" or the "Little Red Dot", is a sovereign city-state in Southeast Asia, and the world's only island city-state. It lies one degree (137 km) north of the equator, south of the southernmost tip of continental Asia and peninsular Malaysia, with Indonesia's Riau Islands to the south. Singapore's territory consists of a diamond-shaped main island along with 62 other islets. Since independence, extensive land reclamation has increased its total size by 23% (130 km), and its greening policy has covered the densely populated island with tropical flora, parks and gardens.  - The Igan River ( Malay : Sungai Igan ) is a river in Sarawak , Malaysia . It joins the Sungai Rajang in Sibu . The river is still used as the primary method of travel to a number of rural districts in Sarawak .  - Malaysia is a federal constitutional monarchy located in Southeast Asia. It consists of thirteen states and three federal territories and has a total landmass of separated by the South China Sea into two similarly sized regions, Peninsular Malaysia and East Malaysia (Malaysian Borneo). Peninsular Malaysia shares a land and maritime border with Thailand and maritime borders with Singapore, Vietnam, and Indonesia. East Malaysia shares land and maritime borders with Brunei and Indonesia and a maritime border with the Philippines and Vietnam. The capital city is Kuala Lumpur, while Putrajaya is the seat of the federal government. With a population of over 30 million, Malaysia is the 44th most populous country. The southernmost point of continental Eurasia, Tanjung Piai, is in Malaysia. Located in the tropics, Malaysia is one of 17 megadiverse countries on earth, with large numbers of endemic species.  - Indonesia (or ; Indonesian: ), officially the Republic of Indonesia, is a unitary sovereign state and transcontinental country located mainly in Southeast Asia with some territories in Oceania. Situated between the Indian and Pacific oceans, it is the world's largest island country, with more than seventeen thousand islands. At , Indonesia is the world's 14th-largest country in terms of land area and world's 7th-largest country in terms of combined sea and land area. It has an estimated population of over 260 million people and is the world's fourth most populous country, the most populous Austronesian nation, as well as the most populous Muslim-majority country. The world's most populous island of Java contains more than half of the country's population.  - East Malaysia ("Malaysia Timur"), also known as Sabah, Sarawak and Labuan ("Sabah, Sarawak dan Labuan") or Malaysian Borneo, is the part of Malaysia located on the island of Borneo. It consists of the Malaysian states of Sabah, Sarawak, and the Federal Territory of Labuan. It lies to the east of Peninsular Malaysia (West Malaysia), which is located on the Malay Peninsula. The two are separated by the South China Sea. While East Malaysia is less populated and less developed than West Malaysia, its land mass is larger and it has notably more natural resources, chiefly oil and gas reserves.    What is the relationship between 'igan river' and 'south china sea'?
Answer:
mouth of the watercourse