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;

namespace ALDS1_10_A
{
    class Program
    {
        public void Proc()
        {
            int N = int.Parse(Console.ReadLine());
            int output = fibonacci(N);
            Console.WriteLine(output);
        }

        static void Main(string[] args)
        {
            Program prg = new Program();
            prg.Proc();
        }

        public int fibonacci(int N)
        {
            int[] arr = new int[N + 1];
            arr[0] = 1;
            arr[1] = 1;
            for (int i = 2; i <= N; i++)
            {
                arr[i] = arr[i - 1] + arr[i - 2];
            }
            return arr[N];
        }
    }
}