/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
	String a = "aabbaaa";
        System.out.println(alternatingCharacters(a));
	}
	static String alternatingCharacters(String s) {
        StringBuilder sb = new StringBuilder(s);
        try {
            for (int i = 0; i < sb.length(); i++) {
                while (i + 1 < sb.length() && sb.charAt(i) == sb.charAt(i + 1)) {
                    sb = sb.deleteCharAt(i);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
 
        return sb.toString();
    }
}

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