With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Machu Picchu was built with dry-stone walls.
text_B: On the Front Line may refer to  :. On the Front Line -LRB- The Casualties album -RRB- , 2004. On the Front Line -LRB- Dan Seals album -RRB- , 1986
not_related.