Problem:
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Fibonacci Number

Write a program which prints $n$-th fibonacci number for a given integer $n$. The $n$-th fibonacci number is defined by the following recursive formula:

\begin{equation*}
fib(n)= \left \{
\begin{array}{ll}
1　 & (n = 0) \\
1　 & (n = 1) \\
fib(n - 1) + fib(n - 2) & \\
\end{array}
\right.
\end{equation*}

Input

An integer $n$ is given.

output

Print the $n$-th fibonacci number in a line.

Constraints

$0 \leq n \leq 44$

Sample Input 1

3

Sample Output 1

3

Solution in C# (judge verdict: Accepted)

using System;

class Program{
    public static void Main(){
        var n=int.Parse(Console.ReadLine());
        var fib=new int[n+2];
        fib[0]=fib[1]=1;
        for (var i=2; i<=n; i++) {
            fib[i]=fib[i-1]+fib[i-2];
        }
        Console.WriteLine(fib[n]);
    }
}