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: Time Limit Exceeded)

import java.util.Scanner;
public class Main {
    public static void main (String[] args) {
	Scanner scan = new Scanner (System.in);
	int n = scan.nextInt();
	System.out.println(fibonacci(n));
    }
    static int fibonacci (int n) {
	if (n < 0) {
	    return 0;
	}
	if (n == 0 || n == 1) {
	    return 1;
	}
	return fibonacci(n-1) + fibonacci(n-2);
    }
}