With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: The Celtic F.C. is a club.
text_B: Thomas Donnelly Doubleday -LRB- February 18 , 1816 -- May 11 , 1864 -RRB- was an American bookstore owner and a Union Army officer in the American Civil War .. Union Army. Union Army. American Civil War. American Civil War
not_related.