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 JavaScript (judge verdict: Accepted)

function fib(fibs, time) {
    if(time === 0 || time === 1) return fibs[time] = 1;
    if(fibs[time]) return fibs[time];

    return fibs[time] = fib(fibs, time - 1) + fib(fibs, time - 2);
}

function main(_stdin){
    const stdin = _stdin.split('\n');
    const a = parseInt(stdin.shift(), 10);

   console.log(fib([1], a));
}


main(require('fs').readFileSync('/dev/stdin', 'utf8'));