The toothpaste mouth of a bottle of toothpaste is circular with a diameter of about 1 cm. Xiao Ming squeezes out 1cm-long toothpaste to brush his teeth every morning and evening, and he has used it for 30 days. What is the volume of this bottle of toothpaste in liters?
一瓶牙膏的牙膏口为圆形，直径约1cm．小明每天早、晚挤出1cm长的牙膏刷牙，刚好用了30天，请问这瓶牙膏的容积为多少升？
<gadget id="calculator">0.000785 * 2 * 30</gadget>
<output>0.0471</output>

<result>0.0471</result>