// ********************************** Capture button's click event ***********************************
 void MyButtonClick(object sender, EventArgs e)
 {
     try
     {
         Button button = sender as Button;
         string szTemp = "";
         if (!liszSymbols.Contains(button.Content) && button.Content.ToString() != "Enter" && boClearList)
         {
             CurrentText.Text = "";
             boClearList      = false;
         }
         if (button.Content.ToString() == "C")
         {
             ClearLists();
             CurrentText.Text = "";
         }
         else if (button.Content.ToString() == "<")
         {
             if (CurrentText.Text.Length != 0)
             {
                 CurrentText.Text = CurrentText.Text.Remove(CurrentText.Text.Length - 1, 1);
             }
         }
         else if (button.Content.ToString() != "Enter")
         {
             if (!liszSymbols.Contains(button.Content))
             {
                 if (button.Content.ToString() == "." && !CurrentText.Text.Contains("."))
                 {
                     CurrentText.Text += button.Content.ToString();
                 }
                 else if (button.Content.ToString() != ".")
                 {
                     CurrentText.Text += button.Content.ToString();
                 }
             }
             else
             {
                 lidoValues.Add(double.Parse(CurrentText.Text));
                 liszOperations.Add(button.Content.ToString());
                 HistoryText.Text += CurrentText.Text + button.Content.ToString();
                 CurrentText.Text  = "";
             }
         }
         else if (button.Content.ToString() == "Enter")
         {
             if (!string.IsNullOrEmpty(CurrentText.Text))
             {
                 lidoValues.Add(double.Parse(CurrentText.Text));
                 if (button.Content.ToString() != "C")
                 {
                     HistoryText.Text += CurrentText.Text;
                     szTemp            = HistoryText.Text;
                 }
                 double doResutl = 0;
                 for (int i = 0; i < liszOperations.Count; i++)
                 {
                     doResutl          = DoOperation(lidoValues[i], lidoValues[i + 1], liszOperations[i]);
                     lidoValues[i + 1] = doResutl;
                 }
                 if (doResutl != 0)
                 {
                     CurrentText.Text = doResutl.ToString("N4");
                 }
                 else
                 {
                     CurrentText.Text = "0";
                 }
                 ClearLists();
                 boClearList = true;
                 liszOperationsHistory.Insert(0, $"{szTemp} = {CurrentText.Text}");
             }
         }
         CurrentText.Focus();
     }
     catch
     {
         AlertBar("Invalid input", 2);
     }
 }