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)

const memoize = function(proc){
    const cache = {};

    const helper = (n) => {
        if(!cache[n]){
            cache[n] = proc(n);
        }
        return cache[n];
    }

    return helper;
}

const fib = memoize((n) => {
    if(n < 2){
        return 1;
    }
    return fib(n - 1) + fib(n - 2);
});

let input = require('fs').readFileSync('/dev/stdin', 'utf8').split("\n");
console.log(fib(Number(input[0])));