diff --git a/CMakeLists.txt b/CMakeLists.txt
index 527b984..ed99c37 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -17,6 +17,7 @@ set(CMAKE_CXX_STANDARD 17)
 
 set(SOURCE_FILES
   src/regular/RegularTree.cpp
+  src/regular/RegularTreeNode.cpp
   )
 
 set(TEST_FILES
diff --git a/src/regular/RegularTree.cpp b/src/regular/RegularTree.cpp
index 712c3d2..3cde403 100644
--- a/src/regular/RegularTree.cpp
+++ b/src/regular/RegularTree.cpp
@@ -1,190 +1,6 @@
 #include "regular/RegularTree.hpp"
-#include <iostream>
-#include <exception>
 
 namespace regular {
-RegularTree::Node::Node() {}
-RegularTree::Node::Node(Type type) : type(type) {}
-
-void RegularTree::Node::Parse(const std::string& regular) {
-  type = Type::Addition;
-  ParseCurrentType(std::string_view(regular.c_str(), regular.size()));
-  Compression();
-}
-
-void RegularTree::Node::Print() const {
-  Print(0);
-}
-
-void RegularTree::Node::ParseCurrentType(const std::string_view regular) {
-  const size_t n = regular.size();
-  children.clear();
-  word.clear();
-
-  auto AddChild = [this](const std::string_view regular) {
-    this->children.push_back(std::make_unique<Node>(Type::Addition));
-    this->children.back()->ParseCurrentType(regular);
-  };
-
-  if (n == 1) {
-    type = Type::Word;
-  }
-
-  if (type == Type::Addition) {
-    int balance = 0;
-    int begin_child = 0;
-    bool wrapped_brackets = (regular[0] == '(');
-
-    for (size_t i = 0; i < n; ++i) {
-      if (regular[i] == '(') {
-        ++balance;
-      } else if (regular[i] == ')') {
-        --balance;
-      }
-
-      if (regular[i] == '|') {
-        if (balance == 0) {
-          AddChild(regular.substr(begin_child + wrapped_brackets, i -
-                                     begin_child - 2 *
-                                     wrapped_brackets));
-          begin_child = i + 1;
-
-          if (i + 1 < n)
-            wrapped_brackets = (regular[i + 1] == '(');
-        }
-      } else {
-        if (i + 1 == n) {
-          if (children.size() == 0) {
-            type = Type::Concatenation;
-            break;
-          } else {
-            AddChild(regular.substr(begin_child + wrapped_brackets, i -
-                                    begin_child + 1 - 2 *
-                                    wrapped_brackets));
-            begin_child = i + 1;
-            if (i + 1 < n)
-              wrapped_brackets = (regular[i + 1] == '(');
-          } 
-        } else if (balance == 0) {
-          wrapped_brackets = false;
-        }
-      } 
-    }
-  }
-
-  if (type == Type::Concatenation) {
-    int balance = 0;
-    int begin_child = 0;
-
-    for (size_t i = 0; i < n; ++i) {
-      if (regular[i] == '(') {
-        ++balance;
-        if (balance == 1) {
-          if (begin_child < i) {
-            AddChild(regular.substr(begin_child, i - begin_child));
-            begin_child = i + 1;
-          }
-        } 
-      } else if (regular[i] == ')') {
-        --balance;
-        if (balance == 0) {
-          AddChild(regular.substr(begin_child + 1, i - begin_child - 1));
-          begin_child = i + 1;
-        }
-      } else if (i + 1 == n) {
-        if (balance != 0) {
-          throw std::logic_error("invalid regular");
-        }
-        if (children.size() == 0) {
-          type = Type::Word;
-          break;
-        } else {
-          AddChild(regular.substr(begin_child, i - begin_child + 1));
-          begin_child = i + 1;
-        } 
-      } else if (balance == 0) {
-        if (regular[i] == '+') {
-          if (begin_child < i) {
-            AddChild(regular.substr(begin_child, i - begin_child));
-          }
-          children.back()->modifier = Modifier::Plus;
-          begin_child = i + 1;
-        } else if (regular[i] == '*') {
-          if (begin_child < i) {
-            AddChild(regular.substr(begin_child, i - begin_child));
-          }
-          children.back()->modifier = Modifier::Star;
-          begin_child = i + 1;
-        }
-      }
-    }
-  }
-
-  if (type == Type::Word) {
-    bool exist_modifire = regular.back() == '+' || regular.back() == '*';
-    if (regular.back() == '+') {
-      modifier = Modifier::Plus;
-    } else if (regular.back() == '*') {
-      modifier = Modifier::Star;
-    }
-    for (size_t i = 0; i < n - exist_modifire; ++i) {
-      if (regular[i] == '|' || regular[i] == '(' || regular[i] == ')') {
-        throw std::logic_error("invalid regular");
-      }
-      word += regular[i];
-    }
-  }
-}
-
-void RegularTree::Node::Compression() {
-  for (auto& i: children) {
-    i->Compression();
-  }
-  if (children.size() == 1 && modifier == Modifier::None) {
-    auto tmp = std::move(*children[0]);
-    *this = std::move(tmp);
-  }
-}
-
-void RegularTree::Node::Print(int nesting_level) const {
-  auto PrintNesingLevel = [](int nesting_level) {
-    for (int i = 0; i < nesting_level; ++i) {
-      std::cout << "  ";
-    }
-  };
-
-  PrintNesingLevel(nesting_level);
-  if (type == Type::Addition) {
-    std::cout << "Addition";
-    if (modifier == Modifier::Plus) {
-      std::cout << "+";
-    } else if (modifier == Modifier::Star) {
-      std::cout << "*";
-    }
-    std::cout << " " << std::to_string(children.size()) << ":" << std::endl;
-  } else if (type == Type::Concatenation) {
-    std::cout << "Concatenation";
-    if (modifier == Modifier::Plus) {
-      std::cout << "+";
-    } else if (modifier == Modifier::Star) {
-      std::cout << "*";
-    }
-    std::cout << " " << children.size() << ":" << std::endl;
-  } else if (type == Type::Word) {
-    std::cout << "Word";
-    if (modifier == Modifier::Plus) {
-      std::cout << "+";
-    } else if (modifier == Modifier::Star) {
-      std::cout << "*";
-    }
-    std::cout << ": " << word << std::endl;
-  }
-
-  for (const auto& i: children) {
-    i->Print(nesting_level + 1);
-  }
-}
-
 RegularTree::RegularTree(const std::string& regular) {
   node_.Parse(regular);
 }
diff --git a/src/regular/RegularTreeNode.cpp b/src/regular/RegularTreeNode.cpp
new file mode 100644
index 0000000..7b4637b
--- /dev/null
+++ b/src/regular/RegularTreeNode.cpp
@@ -0,0 +1,185 @@
+#include "regular/RegularTree.hpp"
+#include <iostream>
+
+using Node = regular::RegularTree::Node;
+Node::Node() {}
+Node::Node(Type type) : type(type) {}
+
+void Node::Parse(const std::string& regular) {
+  type = Type::Addition;
+  ParseCurrentType(std::string_view(regular.c_str(), regular.size()));
+  Compression();
+}
+
+void Node::Print() const {
+  Print(0);
+}
+
+void Node::ParseCurrentType(const std::string_view regular) {
+  const size_t n = regular.size();
+  children.clear();
+  word.clear();
+
+  auto AddChild = [this](const std::string_view regular) {
+    this->children.push_back(std::make_unique<Node>(Type::Addition));
+    this->children.back()->ParseCurrentType(regular);
+  };
+
+  if (n == 1) {
+    type = Type::Word;
+  }
+
+  if (type == Type::Addition) {
+    int balance = 0;
+    int begin_child = 0;
+    bool wrapped_brackets = (regular[0] == '(');
+
+    for (size_t i = 0; i < n; ++i) {
+      if (regular[i] == '(') {
+        ++balance;
+      } else if (regular[i] == ')') {
+        --balance;
+      }
+
+      if (regular[i] == '|') {
+        if (balance == 0) {
+          AddChild(regular.substr(begin_child + wrapped_brackets, i -
+                                     begin_child - 2 *
+                                     wrapped_brackets));
+          begin_child = i + 1;
+
+          if (i + 1 < n)
+            wrapped_brackets = (regular[i + 1] == '(');
+        }
+      } else {
+        if (i + 1 == n) {
+          if (children.size() == 0) {
+            type = Type::Concatenation;
+            break;
+          } else {
+            AddChild(regular.substr(begin_child + wrapped_brackets, i -
+                                    begin_child + 1 - 2 *
+                                    wrapped_brackets));
+            begin_child = i + 1;
+            if (i + 1 < n)
+              wrapped_brackets = (regular[i + 1] == '(');
+          } 
+        } else if (balance == 0) {
+          wrapped_brackets = false;
+        }
+      } 
+    }
+  }
+
+  if (type == Type::Concatenation) {
+    int balance = 0;
+    int begin_child = 0;
+
+    for (size_t i = 0; i < n; ++i) {
+      if (regular[i] == '(') {
+        ++balance;
+        if (balance == 1) {
+          if (begin_child < i) {
+            AddChild(regular.substr(begin_child, i - begin_child));
+            begin_child = i + 1;
+          }
+        } 
+      } else if (regular[i] == ')') {
+        --balance;
+        if (balance == 0) {
+          AddChild(regular.substr(begin_child + 1, i - begin_child - 1));
+          begin_child = i + 1;
+        }
+      } else if (i + 1 == n) {
+        if (balance != 0) {
+          throw std::logic_error("invalid regular");
+        }
+        if (children.size() == 0) {
+          type = Type::Word;
+          break;
+        } else {
+          AddChild(regular.substr(begin_child, i - begin_child + 1));
+          begin_child = i + 1;
+        } 
+      } else if (balance == 0) {
+        if (regular[i] == '+') {
+          if (begin_child < i) {
+            AddChild(regular.substr(begin_child, i - begin_child));
+          }
+          children.back()->modifier = Modifier::Plus;
+          begin_child = i + 1;
+        } else if (regular[i] == '*') {
+          if (begin_child < i) {
+            AddChild(regular.substr(begin_child, i - begin_child));
+          }
+          children.back()->modifier = Modifier::Star;
+          begin_child = i + 1;
+        }
+      }
+    }
+  }
+
+  if (type == Type::Word) {
+    bool exist_modifire = regular.back() == '+' || regular.back() == '*';
+    if (regular.back() == '+') {
+      modifier = Modifier::Plus;
+    } else if (regular.back() == '*') {
+      modifier = Modifier::Star;
+    }
+    for (size_t i = 0; i < n - exist_modifire; ++i) {
+      if (regular[i] == '|' || regular[i] == '(' || regular[i] == ')') {
+        throw std::logic_error("invalid regular");
+      }
+      word += regular[i];
+    }
+  }
+}
+
+void Node::Compression() {
+  for (auto& i: children) {
+    i->Compression();
+  }
+  if (children.size() == 1 && modifier == Modifier::None) {
+    auto tmp = std::move(*children[0]);
+    *this = std::move(tmp);
+  }
+}
+
+void Node::Print(int nesting_level) const {
+  auto PrintNesingLevel = [](int nesting_level) {
+    for (int i = 0; i < nesting_level; ++i) {
+      std::cout << "  ";
+    }
+  };
+
+  PrintNesingLevel(nesting_level);
+  if (type == Type::Addition) {
+    std::cout << "Addition";
+    if (modifier == Modifier::Plus) {
+      std::cout << "+";
+    } else if (modifier == Modifier::Star) {
+      std::cout << "*";
+    }
+    std::cout << " " << std::to_string(children.size()) << ":" << std::endl;
+  } else if (type == Type::Concatenation) {
+    std::cout << "Concatenation";
+    if (modifier == Modifier::Plus) {
+      std::cout << "+";
+    } else if (modifier == Modifier::Star) {
+      std::cout << "*";
+    }
+    std::cout << " " << children.size() << ":" << std::endl;
+  } else if (type == Type::Word) {
+    std::cout << "Word";
+    if (modifier == Modifier::Plus) {
+      std::cout << "+";
+    } else if (modifier == Modifier::Star) {
+      std::cout << "*";
+    }
+    std::cout << ": " << word << std::endl;
+  }
+
+  for (const auto& i: children) {
+    i->Print(nesting_level + 1);
+  }
+}