title: Having trouble wrapping my head around the "!=" operator and "and" & "or" keywords
body: <p>So say, in a while loop...</p>
  
  <pre><code>var = input()
  while var =! "A" and var =! "B":
      var = input()
  </code></pre>
  
  <p>Here I want it to loop until the user inputs <strong>either</strong> A <em>or</em> B. Now logically, it makes more sense to use "or" instead of "and". But "and" seems to be the one that works. I'm trying to wrap my head around why. I want to get this logic step by step, for both "and" and "or" keywords.</p>
  
  <p>So say the user inputs "C". The while loop will check var does not equal A which is true, and then check if var does not equal B which is also true. So wouldn't that run the loop?</p>
  
  <p>Now using "or" instead, it will check if var is not A and then check if var is not B, if it satisfies either requirements, it will run the loop. So wouldn't "or" be the one that should work?</p>