With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Unapologetic is an environmental protection policy.
text_B: Demetrio is an eighteenth-century Italian opera in 3 acts by the Czech composer Josef Myslivecek .. opera. opera. Josef Myslivecek. Josef Myslivecek. It was the composer 's second setting of a libretto by the Italian poet Metastasio that was first performed in 1731 , one of the most popular of the Metastasian librettos in Myslivecek 's day .. libretto. libretto. Metastasio. Metastasio. For a performance in the 1770s , it would only be expected that a libretto of such age would be abbreviated and altered to suit contemporary operatic taste .. libretto. libretto. The cuts and changes in the text made for the 1779 performance of Myslivecek 's opera are not attributable .. opera. opera. All of Myslivecek 's operas are of the serious type in Italian language referred to as opera seria .. opera. opera. opera seria. opera seria
not_related.