# 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.

* * * *

For installation and learning resources, refer to the
[exercism Racket page](http://exercism.io/languages/racket).

You can run the provided tests through DrRacket, or via the command line.

To run the test through DrRacket, simply open the test file and click the 'Run' button in the upper right.

To run the test from the command line, simply run the test from the exercise directory. For example, if the test suite is called `hello-world-test.rkt`, you can run the following command:

```
raco test hello-world-test.rkt
```

which will display the following:

```
raco test: (submod "hello-world-test.rkt" test)
2 success(es) 0 failure(s) 0 error(s) 2 test(s) run
0
2 tests passed
```

## 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.