import java.util.*;

public class Task3 {
    public static void main(String[] args) {
        var javaList = new HashSet<String>(3);
        var pythonList = new HashSet<String>(3);
        var commonList = new HashSet<String>();
        var differenceSet = new HashSet<String>();

        javaList.add("Maximilian Mayer");
        javaList.add("Emil Faber");
        javaList.add("Anna Müller");

        pythonList.add("Anna Müller");
        pythonList.add("Sebastian Waller");
        pythonList.add("Oliver Stilz");

        commonList.addAll(javaList);
        commonList.addAll(pythonList);

        differenceSet.addAll(javaList);
        differenceSet.retainAll(pythonList);

        System.out.println("Java-Kurs: " + javaList);
        System.out.println("Python-Kurs: " + pythonList);
        System.out.println("Alle Teilnehmer: " + commonList);
        System.out.println("Beide Kurse: " + differenceSet);
    }
}