With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Helike was affected by a tsunami.
text_B: Francis Thomas McDougall -LRB- 1817-16 November 1886 -RRB- was the first Bishop of Labuan and Sarawak from 1849 to 1868 .. Bishop of Labuan and Sarawak. Church of the Province of South East Asia
not_related.