#[Pyth], 5 bytes

    ._.&E

[Try it here.](http://pyth.herokuapp.com/?code=._.%26E&input=13%0A4&debug=0)

I am still not entirely sure I understood. Please comment if this is incorrect. I also am unsure if the `E` at the end can be removed, given the lack of test cases in the question's body. Notice the cute face `._.` :)

[Pyth]: https://pyth.readthedocs.io