There are 3 questions in a knowledge contest, and the full score of each question is 7 points. When giving points, only natural numbers 1, 2, ... 7 points can be given. It is known that the product of the scores of each person's 3 questions after participating in the competition is 36, and any two The scores of each question are not exactly the same, so how many people can participate in the competition at most?
一次知识竞赛共3道题，每题满分7分，给分时只能给出自然数1、2、…7分，已知参加竞赛后每人3道题得分的乘积都是36，而且任意二人各题得分不完全相同，那么参加竞赛最多有多少人．
<gadget id="calculator">3 + 3 + 6</gadget>
<output>12</output>

<result>12</result>