CF1514C.Product 1 Modulo N

Now you get Baby Ehab's first words: "Given an integer $n$, find the longest subsequence of $[1,2, \ldots, n-1]$ whose product is $1$ modulo $n$." Please solve the problem.

A sequence $b$ is a subsequence of an array $a$ if $b$ can be obtained from $a$ by deleting some (possibly all) elements. The product of an empty subsequence is equal to $1$.

现在你得到了 Baby Ehab 的第一句话：“给定一个整数 $n$，找出 $[1,2, \ldots, n-1]$ 的最长子序列，使其乘积模 $n$ 等于 $1$。” 请解决该问题。

序列 $b$ 是数组 $a$ 的一个子序列，当且仅当 $b$ 可通过从 $a$ 中删除若干（可能全部）元素得到。空子序列的乘积定义为 $1$。

The only line contains the integer $n$ ($2 \le n \le 10^5$).

唯一的一行包含一个整数 $n$（$2 \le n \le 10^5$）。

The first line should contain a single integer, the length of the longest subsequence.

The second line should contain the elements of the subsequence, in increasing order.

If there are multiple solutions, you can print any.

第一行应包含一个整数，表示最长子序列的长度。

第二行应包含该子序列的元素，按升序排列。

如果存在多个解，输出任意一个即可。

In the first example, the product of the elements is $6$ which is congruent to $1$ modulo $5$. The only longer subsequence is $[1,2,3,4]$. Its product is $24$ which is congruent to $4$ modulo $5$. Hence, the answer is $[1,2,3]$.

在第一个例子中，元素的乘积为 $6$，模 $5$ 同余于 $1$。唯一更长的子序列是 $[1,2,3,4]$，其乘积为 $24$，模 $5$ 同余于 $4$。因此，答案为 $[1,2,3]$。