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 JAVA (judge verdict: Runtime Error)

import java.util.Scanner;

class Main {
	static Integer[] F = new Integer[44];

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println(fibonacci(scanner.nextInt()));
	}
	
	static int fibonacci(int n) {
		if (n == 0 || n == 1) {
			return 	F[n] = 1;
		} else if (F[n] != null) {
			return F[n];
		} else {
			return F[n] = fibonacci(n - 2) + fibonacci(n - 1);
		}
	}
}