At the art festival, the students used 64 potted flowers to form a two-layer hollow square, and later decided to add a layer outside to form a three-layer square. How many potted flowers are needed at least?
艺术节上，同学们用64盆花排出一个两层空心方阵，后来又决定在外面增加一层成为三层方阵，至少需要多少盆花？
<gadget id="calculator">64 + 8</gadget>
<output>72</output>

<gadget id="calculator">72 / 2</gadget>
<output>36</output>

<gadget id="calculator">36 + 8</gadget>
<output>44</output>

<result>44</result>