CF19C.Deletion of Repeats

Once Bob saw a string. It contained so many different letters, that the letters were marked by numbers, but at the same time each letter could be met in the string at most 10 times. Bob didn't like that string, because it contained repeats: a repeat of length x is such a substring of length 2_x_, that its first half coincides character by character with its second half. Bob started deleting all the repeats from the string. He does it as follows: while it's possible, Bob takes the shortest repeat, if it is not unique, he takes the leftmost one, and deletes its left half and everything that is to the left of this repeat.

You're given the string seen by Bob. Find out, what it will look like after Bob deletes all the repeats in the way described above.

有一天，Bob 看到了一个字符串。该字符串包含大量不同的字母，这些字母用数字标记；同时，每个字母在字符串中至多出现 10 次。Bob 不喜欢这个字符串，因为它含有“重复段”：长度为 $x$ 的重复段是指一个长度为 $2x$ 的子串，其前半部分与后半部分逐字符完全相同。Bob 开始从字符串中删除所有重复段。他的删除方式如下：只要字符串中还存在重复段，他就找出最短的重复段；若存在多个同样最短的重复段，则取最左边的那个；然后，他将该重复段的左半部分以及该重复段左侧的所有字符全部删除。

现给出 Bob 所看到的原始字符串，请你求出：按照上述规则删除完所有重复段后，最终的字符串是什么样子。

The first input line contains integer n (1 ≤ n ≤ 105) — length of the string. The following line contains n space-separated integer numbers from 0 to 109 inclusive — numbers that stand for the letters of the string. It's guaranteed that each letter can be met in the string at most 10 times.

第一行输入包含一个整数 $n$（$1 \leq n \leq 10^5$）—— 字符串的长度。
接下来一行包含 $n$ 个用空格分隔的整数，每个数的取值范围为 $0$ 到 $10^9$（含端点）—— 这些数字代表字符串中的字母。
保证字符串中每个字母最多出现 $10$ 次。

In the first line output the length of the string's part, left after Bob's deletions. In the second line output all the letters (separated by a space) of the string, left after Bob deleted all the repeats in the described way.

第一行输出 Bob 删除后剩余字符串部分的长度。
第二行输出 Bob 按照上述方式删除所有重复字母后剩余的所有字母（用空格分隔）。