<p>The <b>Fibonacci numbers</b>, commonly denoted <code>F(n)</code> form a sequence, called the <b>Fibonacci sequence</b>, such that each number is the sum of the two preceding ones, starting from <code>0</code> and <code>1</code>. That is,</p>

<pre>
F(0) = 0, F(1) = 1
F(n) = F(n - 1) + F(n - 2), for n &gt; 1.
</pre>

<p>Given <code>n</code>, calculate <code>F(n)</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> n = 2
<strong>Output:</strong> 1
<strong>Explanation:</strong> F(2) = F(1) + F(0) = 1 + 0 = 1.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> n = 3
<strong>Output:</strong> 2
<strong>Explanation:</strong> F(3) = F(2) + F(1) = 1 + 1 = 2.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> n = 4
<strong>Output:</strong> 3
<strong>Explanation:</strong> F(4) = F(3) + F(2) = 2 + 1 = 3.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>0 &lt;= n &lt;= 30</code></li>
</ul>

class Solution {
public:
    int fib(int n) {
       if(n==0){return 0;}
       if(n==1){return 1;}
       return fib(n-1)+fib(n-2);
    // if(n<=1){
    //     return n;
    // }
    // else{
    // int fib[n+1];
    // fib[0]=0;
    // fib[1]=1;
    // for(int i=2;i<=n;i++){
    //     fib[i]=fib[i-1]+fib[i-2];
    // }
    // return fib[n];
    // }
    }
};
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