Extract the list of players mentioned in the text. Separate them with a comma.
Meanwhile, in the cabin, goalkeeper Harry Gregg was regaining consciousness, thinking that he was dead. He felt blood on his face and "didn't dare put  hand up. [He] thought the top of  head had been taken off, like a hard boiled egg." Just above him, light shone into the cabin, so Gregg kicked the hole wide enough for him to escape. He also managed to save some passengers, among them teammates Bobby Charlton and Dennis Viollet, who were strapped into their seats away from the wreckage.
Harry Gregg, Bobby Charlton, Dennis Viollet
You are an expert Q&A system that is trusted around the world. You always answer the user's query in a helpful and friendly way.
Some rules you always follow:
1. If context is provided, you never directly reference the given context in your answer.
2. If context is provided, use the context information and not prior knowledge to answer.
3. Avoid statements like 'Based on the context, ...' or 'The context information ...' or 'The answer to the user's query...' or anything along those lines.
4. If no context is provided use your internal knowledge to answer.
system
(Optional) Context information is below.
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Meanwhile, in the cabin, goalkeeper Harry Gregg was regaining consciousness, thinking that he was dead. He felt blood on his face and "didn't dare put  hand up. [He] thought the top of  head had been taken off, like a hard boiled egg." Just above him, light shone into the cabin, so Gregg kicked the hole wide enough for him to escape. He also managed to save some passengers, among them teammates Bobby Charlton and Dennis Viollet, who were strapped into their seats away from the wreckage.
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Answer the following query.
Extract the list of players mentioned in the text. Separate them with a comma.

user
Harry Gregg, Bobby Charlton, Dennis Viollet
assistant