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;
using System.Linq;
using System.IO;
using System.Text;
using System.Collections;
using System.Collections.Generic;
 
class Program
{
    static void Main()
    {
        int n = int.Parse(Console.ReadLine());
        Console.WriteLine(Fibonacci(n));
    }

    const int MaxN = 44;
    static int[] F = new int[MaxN + 1];
    static int Fibonacci(int i)
    {
        if(F[i] != 0) return F[i];
        else if(i == 0 || i == 1) return F[i] = 1;
        else return F[i] = Fibonacci(i - 1) + Fibonacci(i - 2);
    }
}