How many small squares of 1 square centimeter are used to place a square with a side length of 2 decimeters, just enough to fill it.
一个边长2分米的正方形，用多少个1平方厘米的小正方形去摆，正好摆满．
<gadget id="calculator">2 * 10 * 2 * 10</gadget>
<output>400</output>

<result>400</result>