Problem Description

Remove adjacent pairs of the same character from a string repeatedly until no such pairs remain. Process from left to right, and after each removal, check for new adjacent pairs.

Input Format

A single string containing lowercase letters.

Output Format

The remaining string after all possible pair removals, or empty string if nothing remains.

Constraints

• 1 ≤ string length ≤ 1000

• String contains only lowercase letters

• Remove adjacent identical pairs iteratively

• Continue until no more pairs can be removed

• Return empty string if all characters are removed

Sample Input/Output

Explanation

abbaca → aaca (remove bb) → ca (remove aa). No more adjacent pairs, result: "ca".