using System;

public class Program

{

    public static void Main()

    {

        // Variables to store your TextBox values

        TimeSpan ts;

        int t1;

        // Attempt to parse both your TimeSpan (TextBox4) and your numeric value (TextBox1)

        if(TimeSpan.TryParse("1:08:14", out ts) && Int32.TryParse("3", out t1))

        {

             // Both of your values were grabbed properly, so perform your division

             var result = ts.Seconds / t1;

             // Output your result

             Console.WriteLine(result);

        }

        else

        {

             // Either the TimeSpan or the integer value (or both) could not be read properly 

        }

    }

}