Remove Adjacent Duplicates

Background

Congcong has been organizing his text files recently. He noticed that many texts contain consecutive duplicate characters, which makes the files look messy. To make the text cleaner, he decided to write a program that automatically removes all adjacent duplicate characters, keeping only one instance.

Problem Description

Given a string, recursively return a "cleaned" string where adjacent characters that are the same have been reduced to a single character. For example, "yyzzza" yields "yza".

Input Format

The input is given from standard input in the following format.

s

Output Format

The output is printed to standard output in the following format.

cleaned_s

Sample

yyzzza

yza

abbbcdd

abcd

Hello

Helo

Sample Explanation

For the first sample "yyzzza\