The length is 5 meters, the width is 3 meters, and the height is 28 meters. Nippon Paint is used to paint the walls and ceiling. The area of doors and windows is 4.5 square meters. If 0.5 kilograms of paint is used per square meter, how many kilograms of paint are needed in total?
长5米，宽3米，高28米，现用立邦漆油漆四壁和天花板，扣除门窗的面积4.5平方米，如果每平方米用油漆0.5千克，一共需要多少千克油漆？
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 * 28 * 2</gadget>
<output>280</output>

<gadget id="calculator">3 * 28 * 2</gadget>
<output>168</output>

<gadget id="calculator">168 - 4.5</gadget>
<output>163.5</output>

<gadget id="calculator">15 + 280 + 163.5</gadget>
<output>458.5</output>

<gadget id="calculator">458.5 * 0.5</gadget>
<output>229.25</output>

<result>229.25</result>