Merkkijono

import java.util.*;
import java.lang.*;
import java.io.*;

public class merkkijono
{
    static int length;
    static boolean del = false;
    static boolean done = false;
    public static void main (String[] args) throws java.lang.Exception
    {
        Scanner scanner = new Scanner(System.in);
        String input = scanner.next();
        StringBuilder builder = new StringBuilder(input);
        while(!done){
            done = true;
            for(int i = 0; i < builder.length()-1; i++) {
                while(i+1<builder.length() && builder.charAt(i)==builder.charAt(i+1)){
                    builder.deleteCharAt(i+1);
                    del = true;
                    done = false;
                }
                if(del){
                    builder.deleteCharAt(i);
                    del = false;
                }
            }
        }
        System.out.println(builder.toString());
    }
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: WRONG ANSWER

Test 10

Verdict: ACCEPTED