Grandpa Lou enjoys watching movies on the Hallmark channel, where each movie lasts 90 minutes. On Tuesday, he watched several full-length movies on the Hallmark channel for a total of 4 hours and 30 minutes. On Wednesday, he watched twice as many movies as he did on Tuesday. What is the maximum number of full-length movies Grandpa could have watched during these two days? Let's think step by step and output the final answer within \boxed{}.
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