title: Find if listA contains any elements not in listB
body: <p>I have two lists:</p>
  
  <pre><code>List&lt;int&gt; listA     
  List&lt;int&gt; listB
  </code></pre>
  
  <p>How to check using LINQ if in the <code>listA</code> exists an element wchich deosn't exists in the <code>listB</code> ? I can use the <code>foreach</code> loop but I'm wondering if I can do this using LINQ</p>