With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: A Song of Ice and Fire is a work.
text_B: The history of the San Fernando Valley from its exploration by the 1769 Portola expedition to the annexation of much of it by the City of Los Angeles in 1915 is a story of booms and busts , as cattle ranching , sheep ranching , large-scale wheat farming , and fruit orchards flourished and faded .. Portola expedition. Portola expedition. San Fernando Valley. San Fernando Valley. Throughout its history , settlement in the San Fernando Valley -LRB- usually called simply `` The Valley '' -RRB- was shaped by availability of reliable water supplies and by proximity to the major transportation routes through the surrounding mountains .. San Fernando Valley. San Fernando Valley
not_related.