Alex has not washed his clothes for a month; 18 shirts, 12 pants, 17 sweaters, and 13 jeans are waiting to be washed. Alex's washing machine can wash a maximum of 15 items per cycle. Each cycle takes 45 minutes. How many hours will it take the washing machine to wash all the clothes?
Please reason step by step, and put your final answer within \boxed{}.
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