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.

Sentence1: Susan was invited for lunch at a friends house. Sentence2: On the way to her friends house one of her tires blew out. Sentence3: Susan had to put on the spare tire. Sentence4: She arrived at her friends house 1 hour too late. Sentence5: Thankfully her friends saved her some food.
Friends, Susan