do
{

    try
    {
        Console.WriteLine();
        Console.WriteLine("please enter one of the names shown above. (correct spelling)");
        gasName = Console.ReadLine();    
        
    }
    catch (System.FormatException ex)
    {
        Console.WriteLine("not a gas == " + ex.Message);
        good = false;
    }
    catch (System.OverflowException ex)
    {
        Console.WriteLine("not the right name == " + ex.Message);
    }
    catch (Exception ex)
    {
        Console.WriteLine("error data == " + ex.Data + " == " + ex.Message);
    }
    finally
    {
        Console.WriteLine("will you like to try again? ");
        if (good)
        {
            doAgain = "no";
        }
        else
        {
            doAgain = "yes";
        }
    }

} while (doAgain == "no");

do
{

    try
    {
        Console.WriteLine();
        Console.WriteLine("please enter one of the names shown above. (correct spelling)");
        gasName = Console.ReadLine();    
        
    }
    catch (System.FormatException ex)
    {
        Console.WriteLine("not a gas == " + ex.Message);
        good = false;
    }
    catch (System.OverflowException ex)
    {
        Console.WriteLine("not the right name == " + ex.Message);
    }
    catch (Exception ex)
    {
        Console.WriteLine("error data == " + ex.Data + " == " + ex.Message);
    }
    finally
    {
        Console.WriteLine("will you like to try again? ");
        if (good)
        {
            doAgain = "no";
        }
        else
        {
            doAgain = "yes";
        }
    }

} while (doAgain == "no");