Mrs. Ge witnessed a bank robbery. She noticed that the first three digits of the license plate of the vehicle used by the robbers to escape included the letters M, X, and P, and the last three digits included the numbers 1, 2, and 3, but she couldn't remember the order in which they were arranged. According to such testimony, the police need to check the maximum number of vehicles.
葛太太目击了一起银行抢劫案．她注意到，劫匪逃逸时使用车辆的车牌前三位包括有英文字母M、X和P，后三位包括有数字1、2和3，但已经不记得它们之间的排列顺序．根据这样的证词，警察最多需要查验多少辆车．
<gadget id="calculator">3 * 2 * 1</gadget>
<output>6</output>

<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<gadget id="calculator">36 - 1</gadget>
<output>35</output>

<result>35</result>