In this task, you're given a story (which contains five sentences only). Your task is to find all the characters which are available in the given story.
Q: Sentence1: In the last mile of a marathon only two runners were in contention. Sentence2: They began to pick up their pace and run even faster. Sentence3: One runner slipped on the ground and tripped the other. Sentence4: They both tumbled and fell on the ground. Sentence5: They rested for a few second before getting back up.
A:
Runner, Runners