With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Avatar: The Last Airbender aired for three seasons from 2005 to 2008.
text_B: This article is part of the history of rail transport by country series. history of rail transport by country. history of rail transport by country. The history of rail transport in Mauritius began in the 1860s .. Mauritius. Mauritius. The Mauritian rail network was quickly built and it soon provided service to most of the island .. It was a key factor in the socio-economic development of Mauritius during its period of operation .. Mauritius. Mauritius. However , due to persistent unprofitability from 1948 to 1953 , it was finally closed in 1964 .
not_related.