With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: K2 is one of the world's most difficult mountains to climb.
text_B: Salmo coruhensis is a species of trout , a freshwater salmonid fish .. Salmo. Salmo. trout. trout. salmonid. salmonid. It lives in streams flowing into the Black Sea , in Turkey and possibly Georgia .. Black Sea. Black Sea. Turkey. Turkey. Georgia. Georgia ( country ). This fish is silvery in colour and can grow to 80 cm length .. It lives in clear , flowing water , particularly in middle stretches of the main branches of rivers and streams .. On the other hand , it is also found in short coastal streams .. After spawning it moves to the sea but stays near the river mouths , or in the lower stretches of rivers .. It migrates upstream to breed in October-Nowember .
not_related.