title: How do I do simple user input in python?
body: <p>I'm just playing with input and variables. I'm trying to run a simple function:</p>
  
  <pre><code>slope = (y2-y1)/(x2-x1)
  </code></pre>
  
  <p>I'd like to prompt the user to enter <code>y2</code>, <code>y1</code>, <code>x2</code> and <code>x1</code>. What is the simplest, cleanest way to do this?</p>