PLA soldiers lined up in a hollow rectangular formation. There are four layers on each side, and the outermost layer has 28 people in the long direction and 20 people in the wide direction. How many soldiers are there in this rectangular formation?
解放军战士排成一个中空的长方形阵．每边四层，最外层长的方向有28人，宽的方向有20人，这个长方形阵中共有多少名战士？
<gadget id="calculator">28 - 4</gadget>
<output>24</output>

<gadget id="calculator">24 * 4 * 2</gadget>
<output>192</output>

<gadget id="calculator">20 - 4</gadget>
<output>16</output>

<gadget id="calculator">16 * 4 * 2</gadget>
<output>128</output>

<gadget id="calculator">192 + 128</gadget>
<output>320</output>

<result>320</result>