<p>Write a program to swap odd and even bits in an integer with as few instructions as possible (e.g., bit 0 and bit 1 are swapped, bit 2 and bit 3 are swapped, and so on).</p>



<p><strong>Example1:</strong></p>



<pre>

<strong> Input</strong>: num = 2（0b10）

<strong> Output</strong> 1 (0b01)

</pre>



<p><strong>Example2:</strong></p>



<pre>

<strong> Input</strong>: num = 3

<strong> Output</strong>: 3

</pre>



<p><strong>Note:</strong></p>



<ol>

	<li><code>0 &lt;= num &lt;=</code>&nbsp;2^30 - 1</li>

	<li>The result integer fits into 32-bit integer.</li>

</ol>