Fill a conical container with a height of 21 cm with water, and then pour all the water into a cylindrical container with the same height as the bottom. How many centimeters is the water surface from the mouth of the container?
在一个高21厘米的圆锥形容器里装满水，再将全部的水倒入与它等底等高的圆柱形容器里，水面距离容器口多少厘米．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">21 * (2/3)</gadget>
<output>14</output>

<result>14</result>