Definition: In this task you are given a story and a question regarding that story. You must judge whether the question is answerable based on the info given to you. Label the instances as "Answerable" or "Not Answerable" based on your judgment. the story and the question are separated by a new line character.
Input: A barbarian was walking through the woods one day. He noticed a foreign tribe by his tribe's river. He ran home and warned his fellow tribesman. They ran over to the foreigners and engaged in combat. The other tribe fled and the barbarian and his tribe went home.
Why did He notice a foreign tribe by his tribe 's river?

Answerable