Given a staircase with a <code>number</code> of steps. Count how many <code>distinct</code> ways can you climb the stairs. In one step, you can climb <code>one</code> or <code>two</code> steps
 
<code>Example 1</code>
<pre><code>Input: 1

Output: 1
</code></pre>
<blockquote>
Explanation: One way to go up the stairs
</blockquote>
<code>Example 2</code>
<pre><code>Input: 2

Output: 2
</code></pre>
<blockquote>
Explanation: Two ways climb the stairs:
<ul>
<li>Climbing by one step</li>
<li>Climbing by two steps</li>
</ul>
</blockquote>

27: Climb stairs