title: How to go back multiple pages in ionic 3
body: <p>I have the page flow like below:</p>
  
  <pre><code>A-&gt;B-&gt;C-&gt;D
  </code></pre>
  
  <p>Somehow I will do a function in page"D", after it need to go back page"B".
  How can I achieve that?
  Using .pop() just can go back one page.
  Using .push(B) is also not the solution, because the flow will become:</p>
  
  <pre><code>A-&gt;B-&gt;C-&gt;D-&gt;B
  </code></pre>
  
  <p>The solution I want is:</p>
  
  <pre><code>A-&gt;B
  </code></pre>
  
  <p>Anyone know how to achieve it? Thanks a lot.</p>