An equilateral triangle flower bed was built in Xingfu Community, and 15 pots of chrysanthemums were placed on each side of the flower bed (one pot at each vertex). How many pots were placed in total?
幸福小区内建了一个正三角形的花坛，在花坛的每一边都摆了15盆菊花(每个顶点都有一盆)，一共摆了多少盆？
<gadget id="calculator">15 * 3</gadget>
<output>45</output>

<gadget id="calculator">45 - 3</gadget>
<output>42</output>

<result>42</result>