There is an open space with a length of 20 meters and a width of 16 meters in front of the school teaching building. A circular fountain with a circumference of 31.4 meters is to be built on this open space. The remaining part is to be planted with flowers. How many square meters is the area for planting flowers?
学校教学楼前有一块长20米，宽16米的空地，要在这块空地上修建一个周长是31.4米的圆形喷水池，剩下的部分种花，种花的面积的多少平方米？
<gadget id="calculator">20 * 16</gadget>
<output>320</output>

<gadget id="calculator">31.4 / 3.14 / 2</gadget>
<output>5</output>

<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">320 - 78.5</gadget>
<output>241.5</output>

<result>241.5</result>