Question: In what year did Langfang have a population of 4,358,839 people while Yichun, Heilongjiang have a population of 1,148,126 people?

full_context: Document 1: Suifenhe: Suifenhe () is a county-level city in southeastern Heilongjiang province, People's Republic of China, located situated where the former Chinese Eastern Railway crosses the border with Russia's town of Pogranichny, Primorsky Krai. In January 2014 Suifenhe became the only Chinese city in which trading with Russian Ruble is allowed.
Document 2: Yinma River: The Yinma River () is a 386.8-km-long tributary of the Second Songhua River in center Jilin province of China. The source of river is located in Yitong Manchu Autonomous County and flows generally from south to north across Panshi、Jiutai、Dehui and joins Second Songhua River at Kaoshan of Nong'an County.
Document 3: Langfang: Langfang (), is a prefecture-level city of Hebei Province, which was known as Tianjin Prefecture until 1973. Hebei province was renamed Langfang Prefecture after Tianjin became a municipality and finally upgraded into a prefecture-level city in 1988. Langfang is located approximately midway between Beijing and Tianjin. At the 2010 census, the population of Langfang was 4,358,839, of whom 868,066 lived in the built-up ("or metro") area made of Guangyang and Anci districts; its total area is around 6417.28 km² . Langfang borders Baoding to the southwest, Cangzhou to the south (both prefecture-level cities of Hebei), Beijing to the north and Tianjin to the east. Sanhe City and Dachang Hui County are now conurbated with Beijing, so that they form part of the same built-up area. Langfang is the smallest prefecture-level city of Hebei Province by land area.
Document 4: Handan: Handan () is a prefecture-level city located in the southwestern part of Hebei province, China. It borders Xingtai on the north, and the provinces of Shanxi on the west, Henan on the south and Shandong on the east. At the 2010 census, its population was 9,174,683 inhabitants whom 2,845,790 lived in the built-up ("or metro") area made of 3 urban districts, Handan and Yangyan counties, and Shahe City in Xintai municipality, largely being conurbated now.
Document 5: Weifang: Weifang () is a prefecture-level city in central Shandong province, People's Republic of China. The city borders Dongying to the northwest, Zibo to the west, Linyi to the southwest, Rizhao to the south, Qingdao to the east, and looks out to the Laizhou Bay to the north. Its population was 9,086,241 at the 2010 census, of whom 2,659,938 lived in the built-up ("or metro") area made up of 4 urban districts ("Kuiwen, Weicheng, Hanting and Fangzi") and Changle County largely being urbanized.
Document 6: Yanjiao: Yanjiao () is a town under the administration of Sanhe City in central Hebei province, bordering Tongzhou District, Beijing across the Chaobai River to the west, located 35 km east of Tiananmen Square and 21 km west of Sanhe. It has a population of 250,000, with long-term residents accounting for 147,000 and migrants taking the rest; 97.9% of the population is of Han ethnicity. , it has 55 villages under its administration.
Document 7: Suihua: Suihua () is a prefecture-level city in west-central Heilongjiang province, People's Republic of China, adjacent to Yichun to the east, Harbin, the provincial capital, to the south, Daqing to the west and Heihe to the north. It has 5,418,453 inhabitants at the 2010 census, of whom 877,114 lived in the built-up ("or metro") area made of Beilin District.
Document 8: Shenyang: Shenyang ( ; ), formerly known by its Manchu name Mukden or Fengtian (), is the provincial capital and the largest city of Liaoning Province, People's Republic of China, as well as the largest city in Northeast China by urban population. According to the 2010 census, the city's urban area has 6.3 million inhabitants, while the total population of the Shenyang municipality, which holds the administrative status of a sub-provincial city, is up to 8.1 million. Shenyang's city region includes the ten metropolitan districts of Shenyang "proper", the county-level city of Xinmin, and two counties of Kangping and Faku.
Document 9: Yichun Lindu Airport: Yichun Lindu Airport (IATA: LDS, ICAO: ZYLD) is an airport serving the city of Yichun in northeast China's Heilongjiang Province. It started operations in August 2009, and is capable of serving 142,000 passengers a year. It incorporates a runway measuring 2300 m and is located in a forest approximately 9 km from downtown Yichun.
Document 10: Tongzhou District, Beijing: Tongzhou District (, alternate spellings "Tungchow" "Tungchou" (T'ung-chou), or Tong County during 1914-1997) is a district of Beijing. It is located in southeast Beijing and considered the eastern gateway to the nation's capital. Downtown Tongzhou itself lies around 20 km east of central Beijing, at the northern end of the Grand Canal (on the junction between the Tonghui Canal and the Northern Canal) and at the easternmost end of Chang'an Avenue. The entire district covers an area of 906 km2 , or 6% of Beijing's total area. It had a population of 673,952 at the 2000 Census, and has seen significant growth and development since then, growing to a population of 1,184,000 at the 2010 Census. The district is subdivided into 4 subdistricts, 10 towns, and 1 ethnic township.
Document 11: Heilongjiang: Heilongjiang () is a province of the People's Republic of China. Located in the northeastern part of the country, Heilongjiang is bordered by Jilin to the south and Inner Mongolia to the west. It also shares a China–Russia border with Russia to the north and east. The capital and the largest city of the province is Harbin. Among Chinese provincial level Administrative divisions, Heilongjiang is the 6th largest by total area and the 15th most populous.
Document 12: Yichun, Heilongjiang: Yichun () is a prefecture-level city on the Songhua river in Heilongjiang province, People's Republic of China. The city is separated from Russia by the Amur River and has an international border of 246 km . At the 2010 census, Yichun has a total population of 1,148,126 while 729,202 people live in 15 districts separated by forests. The greening rate of Yichun is up to 83%. The nickname of Yichun is Lindu ().
Document 13: Yilan County, Heilongjiang: Yilan County () is under the administration of Harbin, the capital of Heilongjiang province, People's Republic of China. It is more than 240 km to the east-northeast of central Harbin. Its county seat, which is also called Yilan (Yilan Town, "Yilan zhen"), is located near the confluence of the Mudan River (formerly known as the Hurka River) with the Sungari. The easternmost county-level division of Harbin City, it borders Fangzheng County to the southwest, Tonghe County to the west, as well as the prefecture-level cities of Yichun to the north, Jiamusi to the northeast, Qitaihe to the southeast, and Mudanjiang to the south.
Document 14: Dingzhou: Dingzhou (), formerly Dingxian ( postal: Tingsien) is a county-level city with sub-prefecture-level city status, located under the administration of the prefecture-level city of Baoding in the southwest of Hebei Province in northern China, about halfway between Baoding and Shijiazhuang. As of 2009, Dingzhou had a population of 1.2 million. Dingzhou has 3 subdistricts, 13 towns, 8 townships, and 1 ethnic township. Dingzhou is 196 km southwest of Beijing, 68 km northeast of Shijiazhuang.
Document 15: Yushu, Jilin: Yushu () is a county-level city under the jurisdiction of Changchun, the capital of Jilin province, People's Republic of China. It is more than 140 km to the northeast of central Changchun, and around 100 km south of Harbin. The name of the place means "Elm Tree". The northernmost county-level division of Changchun, it borders Dehui to the southwest as well as the prefecture-level division of Harbin (Heilongjiang) to the northeast.
ground_truth: 2010