Score : $300$ points

Problem Statement

You are given a ciphertext $S$. It can be decrypted by the following procedure:

• Let $T$ be an empty string.
• For each $i = 1, 2, \dots, |S|$ in this order, do the following: ($|S|$ denotes the length of $S$)- if the $i$-th character of $S$ is R, reverse $T$;
  • if the $i$-th character of $S$ is not R, add that character to the end of $T$.
• if the $i$-th character of $S$ is R, reverse $T$;
• if the $i$-th character of $S$ is not R, add that character to the end of $T$.
• After the operation above, if there are two consecutive same characters in $T$, remove those two characters. Repeat this operation as long as it can be done. (We can prove that the final string obtained does not depend on the order the characters are removed.)

Print the string $T$ obtained by this procedure.

Constraints

• $S$ consists of lowercase English letters and R.
• $1 \leq |S| \leq 5 \times 10^5$

Input

Input is given from Standard Input in the following format:

$S$

Output

Print the answer.

ozRnonnoe

zone

We can decrypt it as follows:

• Initially, $T$ is an empty string.
• Add o at the end of $T$, making it o.
• Add z at the end of $T$, making it oz.
• Reverse $T$, making it zo.
• Add n at the end of $T$, making it zon.
• Add o at the end of $T$, making it zono.
• Add n at the end of $T$, making it zonon.
• Add n at the end of $T$, making it zononn.
• Add o at the end of $T$, making it zononno.
• Add e at the end of $T$, making it zononnoe.
• Delete two consecutive ns from $T$, making it zonooe.
• Delete two consecutive os from $T$, making it zone.

hellospaceRhellospace

The answer may be an empty string.