diff --git a/src/DFA/DFAGraph.cpp b/src/DFA/DFAGraph.cpp
index 90f8c40..1024151 100644
--- a/src/DFA/DFAGraph.cpp
+++ b/src/DFA/DFAGraph.cpp
@@ -51,6 +51,7 @@ void DFAGraph::RemoveVertex(size_t number) {
   RemoveFinalVertex(number);
   RemoveStartVertex(number);
   vertexes_.erase(number);
+  if (number == count_vertexes_ - 1) count_vertexes_--;
 }
 
 void DFAGraph::RemoveFinalVertex(size_t number) {
diff --git a/src/converters/DFAToMinDFA.cpp b/src/converters/DFAToMinDFA.cpp
index 5912b6d..4a67245 100644
--- a/src/converters/DFAToMinDFA.cpp
+++ b/src/converters/DFAToMinDFA.cpp
@@ -10,6 +10,7 @@ DFAGraph DFAGraphToMinDFAGraph(DFAGraph&& graph) {
   {
     std::set<char> set_alphabet;
     for (int i = 0; i < n; ++i) {
+      if (!graph.GetVertex(i)) continue;
       for (auto i: graph.GetVertex(i)->GetTransitions()) {
         set_alphabet.insert(i.first);
       }
diff --git a/src/main.cpp b/src/main.cpp
index 1792d0f..47887ed 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -50,17 +50,21 @@ void example2() {
 }
 
 int main() {
+
   {
-    RegularTree r("a*");
+    RegularTree r("(a|b)+bab(a|b)+");
     NFAGraph NFA_tree = RegularToNFAGraph(std::move(r));
     DFAGraph DFA_graph = NFAGraphToDFAGraph(std::move(NFA_tree));
     DFA_graph = DFAGraphToMinDFAGraph(std::move(DFA_graph));
 
-    DFA_graph = DFAGraphToFDFAGraph(std::move(DFA_graph), {'a', 'b', 'c', 'd'});
-    DFA_graph.Print();
+    DFA_graph = DFAGraphToFDFAGraph(std::move(DFA_graph), {'a', 'b'});
     DFA_graph = InvertFDFAGraph(std::move(DFA_graph));
-    return 0;
     DFA_graph = DFAGraphToMinDFAGraph(std::move(DFA_graph));
+    DFA_graph.Print();
+    auto s = DFAGraphToRegular(std::move(DFA_graph));
+    std::cout << s << std::endl;
+    r = RegularTree(s);
+    r.Print();
   }
   return 0;
   RegularTree r("a*");
@@ -74,6 +78,8 @@ int main() {
   dfa = DFAGraphToMinDFAGraph(std::move(fdfa));
   auto s = DFAGraphToRegular(std::move(dfa));
 
-  // RegularTree r("(a|b)+bab(a|b)+");
-  // std::cout << DFAGraphToRegular(DFAGraphToMinDFAGraph(InvertFDFAGraph(DFAGraphToFDFAGraph(DFAGraphToMinDFAGraph(NFAGraphToDFAGraph(RegularToNFAGraph(std::move(r)))), {'a', 'b'})))) << std::endl;
+  /*
+  RegularTree r("(a|b)+bab(a|b)+");
+  std::cout << DFAGraphToRegular(DFAGraphToMinDFAGraph(InvertFDFAGraph(DFAGraphToFDFAGraph(DFAGraphToMinDFAGraph(NFAGraphToDFAGraph(RegularToNFAGraph(std::move(r)))), {'a', 'b'})))) << std::endl;
+   */
 }