Fixed file name, see extended description.

Fixed file name for clearer organization and readability.

You should do this to all of your projects in Exercise1. The reason being is that when someone (including yourself) goes to view /Exercise1 currently they will see something like:

- Exercise 1
- Exercise 10-19
- Exercise 2
- Exercise 20-29
- Exercise 3
- Etc..

Whereas if you were to put the exercises into a numbering system consisting of three digits (IE: 001, 002, 015, 123, etc..) then it would fix the formatting issue and look like the following:

- Exercise001
- Exercise002
- ...
- Exercise023 (or whatever you want to go to.)

Thus making it easier to read, see what exercises are missing, and so forth. It's just a good habit to form in my opinion. Hope I helped. :)