CF363C.Fixing Typos

Many modern text editors automatically check the spelling of the user's text. Some editors even suggest how to correct typos.

In this problem your task to implement a small functionality to correct two types of typos in a word. We will assume that three identical letters together is a typo (for example, word "helllo" contains a typo). Besides, a couple of identical letters immediately followed by another couple of identical letters is a typo too (for example, words "helloo" and "wwaatt" contain typos).

Write a code that deletes the minimum number of letters from a word, correcting described typos in the word. You are allowed to delete letters from both ends and from the middle of the word.

许多现代文本编辑器会自动检查用户输入文本的拼写，有些编辑器甚至会建议如何纠正拼写错误。

在本题中，你的任务是实现一项小型功能，用于纠正单词中的两类拼写错误。我们假设：连续三个相同的字母构成一个拼写错误（例如，单词 helllo 中包含一个拼写错误）；此外，一对相同的字母紧跟着另一对相同的字母也构成一个拼写错误（例如，单词 helloo 和 wwaatt 中均包含拼写错误）。

请编写一段代码，从单词中删除最少数量的字母，以修正上述两类拼写错误。你被允许从单词的开头、结尾以及中间任意位置删除字母。

The single line of the input contains word s, its length is from 1 to 200000 characters. The given word s consists of lowercase English letters.

输入仅包含一行，即单词 $s$，其长度为 $1$ 到 $200000$ 个字符。给定的单词 $s$ 仅由小写英文字母组成。

Print such word t that it doesn't contain any typos described in the problem statement and is obtained from s by deleting the least number of letters.

If there are multiple solutions, print any of them.

输出满足以下条件的字符串 $t$：它不包含题目描述中的任何拼写错误，并且是通过对字符串 $s$ 删除最少数量的字母得到的。

如果存在多个解，输出其中任意一个即可。

The second valid answer to the test from the statement is "heloo".

题目陈述中测试的第二个有效答案是 “heloo”。