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?
Sentence (from "Langfang"): 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 .
Relevant evidence: Yes