How to check if editing an input field?

Hi! I have a problem with UI input field: if the text of the input field is the position of an object, I cannot edit the text because it is immediately reset to the position:
public InputField input; void Update { input.text = "" + transform.position; }
So how can I check if I edit the input field, so that I can stop that the text of the input field is the current position?