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 "Yichun, Heilongjiang"): At the 2010 census, Yichun has a total population of 1,148,126 while 729,202 people live in 15 districts separated by forests.
Relevant evidence: Yes