A cyclist is training for a race. On the first day, he cycles at a speed of 12 miles per hour for 2 hours. On the second day, he increases his speed by 3 miles per hour and cycles for 1.5 hours. On the third day, he doubles his speed from the second day and cycles for 1 hour. How many total miles did he cycle over the three days? Let's think step by step and output the final answer within \boxed{}.
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