With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: The Khmer Empire is the only predecessor of modern Cambodia.
text_B: Hemipneustes is an extinct genus of sea urchins belonging to the family Holasteridae .. Holasteridae. Holasteridae. These semi-infaunal detritivores lived during the Upper Cretaceous period , from 70.6 to 66.043 Ma .. Cretaceous. Cretaceous. Fossils of this genus have been found in the sediments of Netherlands , Belgium , Bulgaria , India , Iran , the Netherlands , Oman and Spain .
not_related.