Select 5 numbers from 1 to 6 and fill them in □ so that the product of the formula: □*(□-□)*(□-□) is as large as possible. What is the maximum value?
从1～6中选出5个数填入□中，使得算式：□*(□-□)*(□-□)的积尽可能的大，这个最大值是多少．
<gadget id="calculator">6 - 1 - 2</gadget>
<output>3</output>

<gadget id="calculator">4 + 5 + 3</gadget>
<output>12</output>

<gadget id="calculator">12 / 3</gadget>
<output>4</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<gadget id="calculator">4 * 4 * 4</gadget>
<output>64</output>

<result>64</result>