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"): 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.
Relevant evidence: No