<p>Write a method to count the number of 2s that appear in all the numbers between 0&nbsp;and n (inclusive).</p>



<p><strong>Example:</strong></p>



<pre>

<strong>Input: </strong>25

<strong>Output: </strong>9

<strong>Explanation: </strong>(2, 12, 20, 21, 22, 23, 24, 25)(Note that 22 counts for two 2s.)</pre>



<p>Note:</p>



<ul>

	<li><code>n &lt;= 10^9</code></li>

</ul>