We have built a very small example app that contains first `FirstController` and `SecondController` class definitions defined in a single file. The files are setup for a simple example in use of navigation controllers and delegation. **You need to write the code to make this work.** See demo:

**If the following movie doesn't play for you, click on the *navPre.mp4* file above**

![demo movie](navPre.mp4)

The way this is intended to work is:
- The FirstController has a label that says "nothing yet". 
- Clicking on "Second":
  - segues to the SecondController, which has a textField. 
  - and the `FirstController` must TELL the `SecondController` to specify **"Change Me!"** as the initial value of it's `TextField`.
- When the user hits the "Back" nav button:
  - the `SecondController` informs the `FirstController` of the  `TextField`'s new value
  - which the `FirstController` sets as it's label's new value.

It's unorthodox, but we want you to write all the code for two controllers together in the supplied box (the "ViewController.swift" file).

You may work on this question in Xcode. 

**Enter the full text of your `ViewController.swift` file (containing the full definitions of both controller types, 
plus anything else you need to define) in the answer field on GradeScope.**

And yes, this should compile and run correctly when we cut and paste into our version of the project.

**Hints:**
- you will need to *prepare()* for the segue.
- a delegate protocol should be involved in returning the value back to the FirstController.