how to display stopwatch ss\fff as string?

hi, i hope theres a good person out there not like before suddenly close my question without help. please be nice with noob.
im using this code to show time for my stopwatch

void OnGUI() {
		GUILayout.Label (System.TimeSpan.FromSeconds (Time.time).ToString ());

it show right with no problem with format hh\mm\ss\fff but what i want is i want to show only second and millisecond. example, 72 second 129 millisecond, actually will show as 72.129 but i want it to be 72129 but i dont have idea how to get it.

i already check in Custom TimeSpan format strings | Microsoft Learn but i dont get what i want. please help

Not too familiar with TimeSpan, but you could just use Mathf.Round(Time.time * 1000F).ToString (). It will give you 72129 instead of 72.129.

Adjust as needed

void OnGUI() {
         GUILayout.Label (string.Format("{0:ss} seconds {0:fff} milliseconds",  System.TimeSpan.FromSeconds (Time.time)));