Which Design pattern is used to create this Logger

static void Main(string[] args)
            {
                  int strText;
                  int a, b ,c;
                  StreamWriter logFile;
                        Console.Write("Name: ");
                        try
                        {
                        strText = Convert.ToInt32(Console.ReadLine());
                        a = Convert.ToInt32(Console.ReadLine());
                        b = Convert.ToInt32(Console.ReadLine());
                        c = a / b;
                                if (!File.Exists("Log.txt"))
                                {
                                        logFile = new StreamWriter("Log.txt");
                                }
                                else
                                {
                                        logFile = File.AppendText("Log.txt");
                                }
                                logFile.WriteLine(DateTime.Now);

                                logFile.WriteLine(strText.ToString());

                                logFile.WriteLine();
                                Console.WriteLine("Log file saved successfully!");
                        }
                        catch (Exception ex)
                        {
                        if (!File.Exists("Log.txt"))
                            {
                            logFile = new StreamWriter("Log.txt");
                            }
                        else
                            {
                            logFile = File.AppendText("Log.txt");
                            }
                                Console.WriteLine("Error: " + ex.Message);
                                logFile.WriteLine("Error: " + ex.Message);
                        }
                        logFile.Close();
                        Console.Read();
                }
            }
        }