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

namespace aizu1
{
    public class Solution
    {
        public static void Main(string[] args)
        {
            int n = int.Parse(Console.ReadLine());
            int[] A =new int[45];
            A[0] = 1;A[1] = 1;

            Console.WriteLine(Fib(A,n));
        }

        public static int Fib(int[] A, int n)
        {
            if (A[n] != 0) return A[n];
            else
            {
                A[n] = Fib(A,n-1) + Fib(A,n - 2);
                return A[n];
            }
        }
    }
}