With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Linux is a software system that manages and provides common services for computer programs in a way that behaves in a manner similar to a Unix system.
text_B: Arnuwanda I was a king of the Hittite empire .. Hittite empire. Hittite empire. He became a ruler by marriage and was very religious .
not_related.