diff --git a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/ProblemMain.java b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/NoFixSetMain.java
similarity index 72%
rename from src/main/java/dev/struchkov/example/hibernate/nbfe/problem/ProblemMain.java
rename to src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/NoFixSetMain.java
index 5964c05..ac230b4 100644
--- a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/ProblemMain.java
+++ b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/NoFixSetMain.java
@@ -1,18 +1,19 @@
-package dev.struchkov.example.hibernate.nbfe.problem;
+package dev.struchkov.example.hibernate.nbfe.no_fix_set;
 
-import dev.struchkov.example.hibernate.nbfe.problem.domain.Post;
+import dev.struchkov.example.hibernate.nbfe.no_fix_set.domain.Post;
 import jakarta.persistence.EntityManager;
 import jakarta.persistence.EntityManagerFactory;
 import jakarta.persistence.Persistence;
 
 import java.util.List;
 
-public class ProblemMain {
+public class NoFixSetMain {
 
     public static void main(String[] args) {
         final EntityManagerFactory emf = Persistence.createEntityManagerFactory("Blog");
         final EntityManager entityManager = emf.createEntityManager();
 
+        final long startTime = System.currentTimeMillis();
         final List<Post> posts = entityManager.createQuery(
                         """
                                 SELECT p
@@ -25,7 +26,9 @@ public class ProblemMain {
                 .setParameter("minId", 1L)
                 .setParameter("maxId", 50L)
                 .getResultList();
+
+        final long finishTime = System.currentTimeMillis();
+        System.out.println("Performance: " + (startTime - finishTime));
     }
 
-
 }
diff --git a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/Post.java b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/Post.java
similarity index 83%
rename from src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/Post.java
rename to src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/Post.java
index 761ba30..eeddac6 100644
--- a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/Post.java
+++ b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/Post.java
@@ -1,4 +1,4 @@
-package dev.struchkov.example.hibernate.nbfe.problem.domain;
+package dev.struchkov.example.hibernate.nbfe.no_fix_set.domain;
 
 import jakarta.persistence.CascadeType;
 import jakarta.persistence.Entity;
@@ -11,8 +11,8 @@ import jakarta.persistence.OneToMany;
 import lombok.Getter;
 import lombok.Setter;
 
-import java.util.ArrayList;
-import java.util.List;
+import java.util.HashSet;
+import java.util.Set;
 
 @Entity
 @Getter
@@ -30,7 +30,7 @@ public class Post {
             cascade = CascadeType.ALL,
             orphanRemoval = true
     )
-    private List<PostComment> comments = new ArrayList<>();
+    private Set<PostComment> comments = new HashSet<>();
 
     @ManyToMany(
             cascade = {
@@ -43,7 +43,7 @@ public class Post {
             joinColumns = @JoinColumn(name = "post_id"),
             inverseJoinColumns = @JoinColumn(name = "tag_id")
     )
-    private List<Tag> tags = new ArrayList<>();
+    private Set<Tag> tags = new HashSet<>();
 
     public void addComment(PostComment postComment) {
         postComment.setPost(this);
diff --git a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/PostComment.java b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/PostComment.java
similarity index 85%
rename from src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/PostComment.java
rename to src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/PostComment.java
index 5e67aca..d875459 100644
--- a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/PostComment.java
+++ b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/PostComment.java
@@ -1,4 +1,4 @@
-package dev.struchkov.example.hibernate.nbfe.problem.domain;
+package dev.struchkov.example.hibernate.nbfe.no_fix_set.domain;
 
 import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
diff --git a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/Tag.java b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/Tag.java
similarity index 81%
rename from src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/Tag.java
rename to src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/Tag.java
index b321125..9f8555b 100644
--- a/src/main/java/dev/struchkov/example/hibernate/nbfe/problem/domain/Tag.java
+++ b/src/main/java/dev/struchkov/example/hibernate/nbfe/no_fix_set/domain/Tag.java
@@ -1,4 +1,4 @@
-package dev.struchkov.example.hibernate.nbfe.problem.domain;
+package dev.struchkov.example.hibernate.nbfe.no_fix_set.domain;
 
 import jakarta.persistence.Entity;
 import jakarta.persistence.GeneratedValue;
diff --git a/src/main/resources/META-INF/persistence.xml b/src/main/resources/META-INF/persistence.xml
index dd2d39d..70b42b9 100644
--- a/src/main/resources/META-INF/persistence.xml
+++ b/src/main/resources/META-INF/persistence.xml
@@ -4,9 +4,9 @@
 http://xmlns.jcp.org/xml/ns/persistence_2_1.xsd">
 
     <persistence-unit name="Blog">
-        <class>dev.struchkov.example.hibernate.nbfe.problem.domain.Post</class>
-        <class>dev.struchkov.example.hibernate.nbfe.problem.domain.PostComment</class>
-        <class>dev.struchkov.example.hibernate.nbfe.problem.domain.Tag</class>
+        <class>dev.struchkov.example.hibernate.nbfe.no_fix_set.domain.Post</class>
+        <class>dev.struchkov.example.hibernate.nbfe.no_fix_set.domain.PostComment</class>
+        <class>dev.struchkov.example.hibernate.nbfe.no_fix_set.domain.Tag</class>
         <exclude-unlisted-classes>true</exclude-unlisted-classes>
         <properties>
             <property name="jakarta.persistence.jdbc.driver" value="org.h2.Driver"/>