Merkkijono

import java.util.*;
 
class merkkijono
{
	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;
					i=0;
				}
			}
		}
		System.out.println(builder.toString());
	}
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: WRONG ANSWER

Test 3

Verdict: ACCEPTED

Test 4

Verdict: WRONG ANSWER

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED