title: missbehaviour of "OR" in python
body: <p>Hy... I'm just learning python. And I have made a program like this :</p>
  
  <pre><code>guess = raw_input("please input something...");
  while (guess != 'h'):
      guess = raw_input("pleae input something again....");
      print(guess);
  
  print("Thanks...");
  </code></pre>
  
  <p>Well... Above program is running well. But when I put "OR" after guess != 'h' like this :</p>
  
  <pre><code>guess = raw_input("please input something...");
  while (guess != 'h') or (guess != 't'):
      guess = raw_input("pleae input something again....");
      print(guess);
  
  print("Thanks...");
  </code></pre>
  
  <p>Above program is running forever in while loop. What's happening there ? I thought the loop will be ended after I input either h or t</p>