#!/usr/bin/env p2sh

let fibonacci = fn(n) {
    if n == 0 {
        return 0;
    } else if n == 1 {
        return 1;
    }

    let a = 0;
    let b = 1;
    let result = 0;
    let i = 2;

    while i <= n {
        result = a + b;
        a = b;
        b = result;
        i = i + 1;
    }

    return result;
}


let n = if len(argv) > 1 {
  int(argv[1])
} else {
 30
};

let t1 = time();
let fib = fibonacci(n);
let t2 = time();
let secs = t2 - t1;

println("fib({}) = {} [took {} secs] ", n, fib, secs);