With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Buckingham Palace is an administrative headquarters in London.
text_B: The RASopathies are developmental syndromes caused by germline mutations -LRB- or in rare cases by somatic mosaicism -RRB- in genes that alter the Ras subfamily and mitogen-activated protein kinases that control signal transduction , including  :. germline. germline. somatic mosaicism. somatic mosaicism. Ras subfamily. Ras subfamily. signal transduction. signal transduction. Capillary malformation-AV malformation syndrome. Capillary malformation-AV malformation syndrome. Arteriovenous malformation. Autoimmune lymphoproliferative syndrome. Autoimmune lymphoproliferative syndrome. Autoimmune lymphoproliferative syndrome. Cardiofaciocutaneous syndrome. Cardiofaciocutaneous syndrome. Cardiofaciocutaneous syndrome. Hereditary gingival fibromatosis type 1. Hereditary gingival fibromatosis type 1. Gingival fibromatosis with hypertrichosis. Neurofibromatosis type 1. Neurofibromatosis type 1. Neurofibromatosis type 1. Noonan syndrome. Noonan syndrome. Noonan syndrome. Costello syndrome , Noonan-like. Costello syndrome. Costello syndrome. Legius syndrome , Noonan-like. Legius syndrome. Legius syndrome. Noonan syndrome with multiple lentigines , formerly called LEOPARD syndrome , Noonan-like. Noonan syndrome. Noonan syndrome. lentigines. lentigines. LEOPARD syndrome. LEOPARD syndrome
not_related.