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: Time Limit Exceeded)

using System;
using System.Linq;
using System.Collections.Generic;
using System.Text;


class A
{
    static int[] F=new int[44];
    public static void Main() {
        int n = int.Parse(System.Console.ReadLine());
        F[0] = 1;
        F[1] = 1;
        Console.WriteLine(fibonacchi(n));
    }
    static int fibonacchi(int n) {
        if (n == 0||n==1) {
            return F[n];
        }
        F[n] = fibonacchi(n - 1) + fibonacchi(n - 2);
        return F[n];
    }
}