Mary is making a model sailboat. She wants to add three sails: a rectangular sail that measures 5 inches by 8 inches and two right triangular sails, one that's 3 inches long at the bottom and 4 inches tall and one that's 4 inches long at the bottom and 6 inches tall. (Remember you can find the area of a triangle by dividing the area of a square with the same height and length by 2). How many square inches of canvas does she need total?
Please reason step by step, and put your final answer within \boxed{}.
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