Dalton, Hunter, and Alex started a Superhero Fan Club. They set a goal to watch as many Superhero movies as they could in one summer. Dalton watched 7 movies, Hunter watched 12, and Alex watched 15. They all watched 2 movies together, but every other movie they watched was different. How many different movies did they see?
Please reason step by step, and put your final answer within \boxed{}.
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