# Phone Number

Clean up user-entered phone numbers so that they can be sent SMS messages.

The **North American Numbering Plan (NANP)** is a telephone numbering system used by many countries in North America like the United States, Canada or Bermuda. All NANP-countries share the same international country code: `1`.

NANP numbers are ten-digit numbers consisting of a three-digit Numbering Plan Area code, commonly known as *area code*, followed by a seven-digit local number. The first three digits of the local number represent the *exchange code*, followed by the unique four-digit number which is the *subscriber number*.


The format is usually represented as
```
(NXX)-NXX-XXXX
```
where `N` is any digit from 2 through 9 and `X` is any digit from 0 through 9.

Your task is to clean up differently formated telephone numbers by removing punctuation and the country code (1) if present.

For example, the inputs
- `+1 (613)-995-0253`
- `613-995-0253`
- `1 613 995 0253`
- `613.995.0253`

should all produce the output

`6139950253`

**Note:** As this exercise only deals with telephone numbers used in NANP-countries, only 1 is considered a valid country code.

## Elm Installation

Refer to the [Exercism help page](http://exercism.io/languages/elm) for Elm
installation and learning resources.

## Writing the Code

The first time you start an exercise, you'll need to ensure you have the
appropriate dependencies installed.

```bash
$ npm install
```

Execute the tests with:

```bash
$ npm test
```

Automatically run tests again when you save changes:

```bash
$ npm run watch
```

As you work your way through the test suite, be sure to remove the `skip <|`
calls from each test until you get them all passing!

## Source

Event Manager by JumpstartLab [http://tutorials.jumpstartlab.com/projects/eventmanager.html](http://tutorials.jumpstartlab.com/projects/eventmanager.html)

## Submitting Incomplete Solutions
It's possible to submit an incomplete solution so you can see how others have completed the exercise.