/*
// Expresiones regulares en java
// https://es.stackoverflow.com/q/145363/127
*/
 
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
	    final String regex = "\\b[A-Z\\d]{1,2}(?:-\\d{1,4}){2}\\b";
	    final String cleanpageone = "PE-13-641 N-12-1236 1-11-778";
 
	    final Pattern pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE);
	    final Matcher matcher = pattern.matcher(cleanpageone);
 
	    while (matcher.find()) {
	        System.out.println(matcher.group(0));
	    }
	}
}

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