/* 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 someString = "CC23QQ21HD32";
		String regex = "((?<=[a-zA-Z])(?=[0-9]))|((?<=[0-9])(?=[a-zA-Z]))";
		System.out.println(Arrays.asList(someString.split(regex)));
	}
}