In the four-digit number composed of the four numbers 1, 2, 3, and 4, 1 is not in the ones place, 2 is not in the tens place, 3 is not in the hundreds place, and 4 is not in the thousands place. How many are there?
由1、2、3、4这四个数字组成的四位数中，1不在个位上，2不在十位上，3不在百位上，4不在千位上，这样的四位数一共有多少个．
<gadget id="calculator">4 * 3 * 2 * 1</gadget>
<output>24</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">24 - 1 - 6 - 8</gadget>
<output>9</output>

<result>9</result>