With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: Pi is the ratio of the distance of the circumference of a circle to the length across the circle.
text_B: Serixia argentea is a species of beetle in the family Cerambycidae .. Cerambycidae. Cerambycidae. Serixia. Serixia. beetle. beetle. It was described by Aurivillius in 1922 .
not_related.