title: Why doesn't the file open? (Python)
body: <p>Whenever I try to input "C.elegans_small.gff", the program gives the print statement of "unable to open". However, I want it to open. Why is this happening?</p>
  
  <pre><code>print("Gene length computation for C. elegans.")
  print()
  file1 = "C.elegans_small.gff"
  file2 = "C.elegans.gff"
  user_input = input("Input a file name: ")
  while user_input != file1 or user_input != file2:
      print("Unable to open file.") 
      user_input = input("Input a file name: ")
      if user_input == file1 or user_input == file2:
          break
  </code></pre>