title: Python Challenge Level 2
body: <p>I am trying to solve Python challenges in <a href="http://www.pythonchallenge.com/" rel="nofollow">pythonchallenge.com</a>. I am in level 2. I was asked to find rare characters in a very large text which is given in the source code of the web page. Here it is:
  <a href="http://www.pythonchallenge.com/pc/def/ocr.html" rel="nofollow">http://www.pythonchallenge.com/pc/def/ocr.html</a></p>
  
  <p>First of all, I don't want any solutions for this. I just want to solve it on my own but I am not an advanced Python programmer. So can you tell me what to study to solve this? I also don't know how to work with files very well. In some clues on forum, it is mentioned that one should use files to solve this. So can you show me what to study?</p>