With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: In Ancient Greece boxing was a well developed sport and enjoyed consistent popularity. In Olympic terms, it was first introduced in the 23rd Olympiad, 688 BC. The boxers would wind leather thongs around their hands in order to protect them. There were no rounds and boxers fought until one of them acknowledged defeat or they had zero energy left to fight. Weight categories were not used, which meant heavyweights had a tendency to dominate. The style of boxing practiced typically featured an advanced left leg stance, with the left arm semi-extended as a guard, in addition to being used for striking, and with the right arm drawn back ready to strike. It was the head of the opponent which was primarily targeted, and there is little evidence to suggest that targeting the body was common.
text_B: If a boxer was no longer able to fight, would the match continue?
NO.