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)

// Fibonacci_Number.cs

using System;

class Fibonacci_Number {
	public static void Main() {

		int n = int.Parse(Console.ReadLine());

		if(n == 0 || n == 1) {
			Console.WriteLine(1);
		} else {

			Console.WriteLine(Fib(n));

		}

	}

	public static int Fib(int n) {

		int[] a = new int[n + 1];
		a[0] = a[1] = 1;

		for(int i = 2; i <= n; i++) {
			a[i] = a[i - 1] + a[i - 2];
		}

		return a[n];

	}

}