import java.util.*;
import java.lang.*;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
 
class Main
{
        public static void main (String[] args) throws java.lang.Exception
        {
			System.out.println(Pattern.matches("^\\[([a-zA-Z]+\\d+)?\\]$","[abc123]"));
			Pattern pattern = Pattern.compile("^\\[([a-zA-Z]+\\d+)?\\]$");
			Matcher matcher = pattern.matcher("[abc123]");
			while (matcher.find()) {
				System.out.println(matcher.group(1));
			}
        }
}

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