A cuboid with a length of 21 cm, a width of 15 cm, and a height of 13 cm. Now cut off a cube as large as possible from it, then another cube as large as possible from the remaining part, and finally another cube as large as possible from the remaining part of the second time. What is the volume in cubic centimeters of the last cut of the cube?
一个长21厘米，宽15厘米，高13厘米的长方体．现在从它上面切下一个尽可能大的正方体，然后从剩下的部分又切一个尽可能大的正方体，最后从第二次剩下的部分再切下一个尽可能大的正方体．最后一次切这个正方体的体积是多少立方厘米．
<gadget id="calculator">7 * 7 * 7</gadget>
<output>343</output>

<result>343</result>