CF932A.Palindromic Supersequence

You are given a string A. Find a string B, where B is a palindrome and A is a subsequence of B.

A subsequence of a string is a string that can be derived from it by deleting some (not necessarily consecutive) characters without changing the order of the remaining characters. For example, "cotst" is a subsequence of "contest".

A palindrome is a string that reads the same forward or backward.

The length of string B should be at most 104. It is guaranteed that there always exists such string.

You do not need to find the shortest answer, the only restriction is that the length of string B should not exceed 104.

给你一个字符串 $A$。请找出一个字符串 $B$，使得 $B$ 是回文串，且 $A$ 是 $B$ 的一个子序列。

字符串的子序列是指通过删除原字符串中若干（不一定连续）的字符、但不改变剩余字符顺序所得到的字符串。例如，“cotst” 是 “contest” 的一个子序列。

回文串是指正读和反读都相同的字符串。

字符串 $B$ 的长度至多为 $10^4$。题目保证这样的字符串 $B$ 一定存在。

你无需找出最短的解，唯一限制是字符串 $B$ 的长度不能超过 $10^4$。

First line contains a string A (1 ≤ |A| ≤ 103) consisting of lowercase Latin letters, where |A| is a length of A.

第一行包含一个字符串 $A$（$1 ≤ |A| ≤ 10^3$），由小写拉丁字母组成，其中 $|A|$ 表示 $A$ 的长度。

Output single line containing B consisting of only lowercase Latin letters. You do not need to find the shortest answer, the only restriction is that the length of string B should not exceed 104. If there are many possible B, print any of them.

输出一行仅包含小写拉丁字母的字符串 B。你无需寻找最短的答案，唯一限制是字符串 B 的长度不得超过 $10^4$。若存在多个可能的 B，输出任意一个即可。

In the first example, "aba" is a subsequence of "aba" which is a palindrome.

In the second example, "ab" is a subsequence of "aabaa" which is a palindrome.

在第一个例子中，“aba”是回文串“aba”的一个子序列。

在第二个例子中，“ab”是回文串“aabaa”的一个子序列。