There is a square flower bed, and flower pots are placed around the flower bed, 4 pots are placed on each side, and all four vertices are placed. How many pots of flowers are needed in total?
有一块正方形的花坛，在花坛的四周都摆上花盆，每边都摆上4盆，四个顶点都要摆，一共需要几盆花？
<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">16 - 4</gadget>
<output>12</output>

<result>12</result>