Problem Statement

harurun is bad at English and writes programming as programing.

We call this way of writing, in which $2$ consecutive identical characters are written as $1$ character, $harurun$ notation.

You are given $1$ string $S$. Output it in $harurun$ notation.

However, a string in which $3$ or more identical characters are consecutive is never given.

The formal problem statement is as follows.

You are given a string $S$.

Output the string $S$ after performing the following operation as many times as possible.

• When $2$ adjacent characters are the same, delete one of them.

However, a string in which $3$ or more identical characters are consecutive, such as abbb, is not given.

(AC has been confirmed with Python3, PyPy3, C, C++17(1z), Java15, Javascript, and Rust, but slow languages such as Bash may not be able to get AC.)

Input

$S$

The string $S$ is given on line $1$.

Constraints

• $S_i (1≤i≤|S|)$ is a lowercase English letter.

• $1≤|S|≤5\times10^6$

• When $S_i$ and $S_{i+1}$ are the same character, $S_{i+1}$ and $S_{i+2}$ are different characters. $(1≤i<|S|-1)$

($S_{i}$ denotes the $i$-th character of $S$, and $|S|$ denotes the length of $S$.)

Output

Output the answer on one line.

Print a newline at the end.

Sample

programming

programing

aabbccb

abcb

abcdefghijklmnopqrstuvwxyz

abcdefghijklmnopqrstuvwxyz