title: Checking non-negative even integer in Python
body: <p>I'm new to programming and currently learning Python. I would like to write a program that :</p>
  
  <ol>
  <li>request user to input a non-negative even integer.</li>
  <li>request the user to input again if not fulfil non-negative even integer.</li>
  </ol>
  
  <pre class="lang-py prettyprint-override"><code>N = input("Please enter an non-negative even integer: ") #request user to input
  </code></pre>
  
  <p>And the criteria checking code is:</p>
  
  <pre class="lang-py prettyprint-override"><code>N == int(N) #it is integer
  N % 2 == 0 #it is even number
  N &gt;=0 # it is non-negative number
  </code></pre>
  
  <p>But how should I combine them?</p>