Given the task definition and input, reply with output. 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: I was excited to go snorkeling for the first time. Sentence2: My friend told me to go to crab island and snorkel. Sentence3: I made a reservation with a tour guide to take me there. Sentence4: I had an amazing time. Sentence5: Someone on the tour caught a seahorse.
I (myself), Tour guide, Someone, My friend