cuboid block of wood with a length of 42 cm, a width of 24 cm, and a height of 36 cm is painted with red paint, and then it is sawed into several small squares of the same size without waste. Then how many small cubes are there that are not painted with red paint on the surface?
一个长42厘米、宽24厘米、高36厘米的长方体木块，表面涂上红漆，再把它锯成若干个相同大小的小正方形体且没有废料．则表面没有涂上红漆的小正方体至少有多少块．
<gadget id="calculator">7 - 2</gadget>
<output>5</output>

<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<gadget id="calculator">6 - 2</gadget>
<output>4</output>

<gadget id="calculator">5 * 2 * 4</gadget>
<output>40</output>

<result>40</result>