With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Leukemia usually begins in the bone marrow and produces abnormal white blood cells.
text_B: Aroab is a village with a population of approximately 5,000 in the ǁKaras Region of southern Namibia .. Region. Regions of Namibia. ǁKaras Region. ǁKaras Region. Namibia. Namibia. It is situated about 170 km south-east of Keetmanshoop on the edge of the Kalahari desert ; the average annual rainfall is about 150-200mm .. Keetmanshoop. Keetmanshoop. Kalahari. Kalahari. Aroab is the district centre of the Keetmanshoop Rural electoral constituency .. Keetmanshoop Rural. Keetmanshoop Rural. Keetmanshoop. Keetmanshoop
not_related.