title: Not Equal to(!=) operation not working in while loop
body: <p>Are there any special rules in regards to using the != operation in a while statement in python. For example I have a loop of code like this</p>
  
  <pre><code>input("f_l value ")
  while f_l != "s" or f_l != "S" or f_l != "q" or f_l != "Q":
      print("Error")
      input("f_l value ")
  print("your f_l is correct")
  </code></pre>
  
  <p>The while loop won't stop and print the value. I don't know why. Any ideas?</p>