diff --git a/ClassRoom.java b/ClassRoom.java
new file mode 100644
index 0000000..8ccdb97
--- /dev/null
+++ b/ClassRoom.java
@@ -0,0 +1,39 @@
+package advanced;
+
+public class ClassRoom {
+    private String id;
+    private String name;
+    private Teacher teacher;
+    
+    public ClassRoom() {
+    }
+    
+    public ClassRoom(String id, String name) {
+        this.id = id;
+        this.name = name;
+    }
+    
+    public void setTeacher(Teacher teacher) {
+        this.teacher = teacher;
+    }
+    
+    public String getId() {
+        return id;
+    }
+    
+    public void setId(String id) {
+        this.id = id;
+    }
+    
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    public Teacher getTeacher() {
+        return teacher;
+    }
+}
\ No newline at end of file
diff --git a/Course.java b/Course.java
new file mode 100644
index 0000000..ad05950
--- /dev/null
+++ b/Course.java
@@ -0,0 +1,59 @@
+package advanced;
+
+public class AdvancedCourse {
+    private int id;
+    private String name;
+    private int credit;
+    private java.util.List<AdvancedCourse> prerequisiteCourses;
+    
+    public AdvancedCourse() {
+        this.prerequisiteCourses = new java.util.ArrayList<>();
+    }
+    
+    public AdvancedCourse(int id, String name, int credit) {
+        this.id = id;
+        this.name = name;
+        this.credit = credit;
+        this.prerequisiteCourses = new java.util.ArrayList<>();
+    }
+    
+    public void addPrerequisiteCourse(AdvancedCourse course) {
+        prerequisiteCourses.add(course);
+    }
+    
+    public void removePrerequisiteCourse(AdvancedCourse course) {
+        prerequisiteCourses.remove(course);
+    }
+    
+    public int getId() {
+        return id;
+    }
+    
+    public void setId(int id) {
+        this.id = id;
+    }
+    
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    public int getCredit() {
+        return credit;
+    }
+    
+    public void setCredit(int credit) {
+        this.credit = credit;
+    }
+    
+    public java.util.List<AdvancedCourse> getPrerequisiteCourses() {
+        return prerequisiteCourses;
+    }
+    
+    public void setPrerequisiteCourses(java.util.List<AdvancedCourse> prerequisiteCourses) {
+        this.prerequisiteCourses = prerequisiteCourses;
+    }
+}
\ No newline at end of file
diff --git a/Parent.java b/Parent.java
new file mode 100644
index 0000000..659b9e5
--- /dev/null
+++ b/Parent.java
@@ -0,0 +1,49 @@
+package advanced;
+
+public class Parent {
+    private String id;
+    private String name;
+    private java.util.List<basic.Student> children;
+    
+    public Parent() {
+        this.children = new java.util.ArrayList<>();
+    }
+    
+    public Parent(String id, String name) {
+        this.id = id;
+        this.name = name;
+        this.children = new java.util.ArrayList<>();
+    }
+    
+    public void addChild(basic.Student student) {
+        children.add(student);
+    }
+    
+    public void removeChild(basic.Student student) {
+        children.remove(student);
+    }
+    
+    public String getId() {
+        return id;
+    }
+    
+    public void setId(String id) {
+        this.id = id;
+    }
+    
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    public java.util.List<basic.Student> getChildren() {
+        return children;
+    }
+    
+    public void setChildren(java.util.List<basic.Student> children) {
+        this.children = children;
+    }
+}
\ No newline at end of file
diff --git a/Student.java b/Student.java
new file mode 100644
index 0000000..ed0720e
--- /dev/null
+++ b/Student.java
@@ -0,0 +1,50 @@
+package advanced;
+
+public class AdvancedStudent {
+    private int id;
+    private String name;
+    private Parent parent;
+    private java.util.List<basic.Grade> grades;
+    
+    public AdvancedStudent() {
+        this.grades = new java.util.ArrayList<>();
+    }
+    
+    public AdvancedStudent(int id, String name) {
+        this.id = id;
+        this.name = name;
+        this.grades = new java.util.ArrayList<>();
+    }
+    
+    public int getId() {
+        return id;
+    }
+    
+    public void setId(int id) {
+        this.id = id;
+    }
+    
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    public Parent getParent() {
+        return parent;
+    }
+    
+    public void setParent(Parent parent) {
+        this.parent = parent;
+    }
+    
+    public java.util.List<basic.Grade> getGrades() {
+        return grades;
+    }
+    
+    public void setGrades(java.util.List<basic.Grade> grades) {
+        this.grades = grades;
+    }
+}
\ No newline at end of file
diff --git a/Teacher.java b/Teacher.java
new file mode 100644
index 0000000..3f9fc81
--- /dev/null
+++ b/Teacher.java
@@ -0,0 +1,49 @@
+package advanced;
+
+public class Teacher {
+    private String id;
+    private String name;
+    private java.util.List<ClassRoom> classes;
+    
+    public Teacher() {
+        this.classes = new java.util.ArrayList<>();
+    }
+    
+    public Teacher(String id, String name) {
+        this.id = id;
+        this.name = name;
+        this.classes = new java.util.ArrayList<>();
+    }
+    
+    public void addClass(ClassRoom classRoom) {
+        classes.add(classRoom);
+    }
+    
+    public void removeClass(ClassRoom classRoom) {
+        classes.remove(classRoom);
+    }
+    
+    public String getId() {
+        return id;
+    }
+    
+    public void setId(String id) {
+        this.id = id;
+    }
+    
+    public String getName() {
+        return name;
+    }
+    
+    public void setName(String name) {
+        this.name = name;
+    }
+    
+    public java.util.List<ClassRoom> getClasses() {
+        return classes;
+    }
+    
+    public void setClasses(java.util.List<ClassRoom> classes) {
+        this.classes = classes;
+    }
+}
\ No newline at end of file