/* package whatever; // don't place package name! */

import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
/* 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 s = "CX12345\nCX14584\nJB145888\nJD748452\nCX12345\nLM45855";
		String p = "(?s)\\b((?!CR|cr)[A-Za-z]{2}\\d{5,6})\\b(?!.*\\b\\1\\b)";
		Pattern pattern = Pattern.compile(p);
		Matcher matcher = pattern.matcher(s);
		while (matcher.find()){
			System.out.println(matcher.group(0)); 
		} 
	}
}