Master Wang first dug out two squares with a side length of 1 meter on a wall that is 8 meters long and 5 meters wide, and then painted the wall. How big is the part that needs to be painted?
王师傅先在一面长8米、宽5米的墙壁上挖出2个边长1米的正方形，然后给墙面部分刷漆，需要刷漆的部分有多大？
<gadget id="calculator">8 * 5</gadget>
<output>40</output>

<gadget id="calculator">1 * 1 * 2</gadget>
<output>2</output>

<gadget id="calculator">40 - 2</gadget>
<output>38</output>

<result>38</result>