Part I:\(i\)Sit down.\(a_i\)（\(a_i\)\(\le\)\(n\)) this position, then\(a_i\)There would be no room for him to sit, and he would have to sit in his preferred seat, which was the\(a_{a_i}\)（\(a_{a_i}\)\(\le\)\(n\)), and so on, if the last person\(k\)The preferred location is\(i\)That is.\(a_k=i,\)That is, he sat back\(i\)This position, that is, he is again connected to the\(i\)The answer is that a ring is formed, so that everyone on the ring can make it to their preferred position and eventually fill the original position of everyone on the ring (i.e., the position designed by the pageant designers) without affecting those outside the ring, as is the case for all rings, and the size of the ring can be added to the answer.