Can't change value of inputfield

I want the User to enter a number and then the script adds an € in the end.So i tried using:

mygame_object_which_is_a_child_of_the_inputfield.GetComponentInParent<InputField>`().Append("€");`

but i get an Error saying:UnityEngine.UI.InputField.Append(string)’ is inaccessible due to its protection level

This is what I would do.

string yourNewValue = mygame_object_which_is_a_child_of_the_inputfield.GetComponentInParent<InputField>().text + "€";

Debug.Log (yourNewValue);

Make sure that you are using UnityEngine.UI when dealing with UI.