#!/usr/local/bin/pike
// -*- mode: pike -*-
// $Id: fibo.pike,v 1.2 2000/12/24 19:10:50 doug Exp $
// http://www.bagley.org/~doug/shootout/
//#pragma strict_types
// "memoized" by rjb@bobo.fuw.edu.pl --> speedup by factor ~100 (!)

object fib = class
{
    static mapping(int:int) cache = ([0:1,1:1]);
    static int `()(int n)
    {
        return cache[n] || (cache[n]=fib(n-2)+fib(n-1));
    }
}();

void
main(int argc, array(string) argv) {
    int n = max((int)argv[-1], 1);
    int steps = n/9000;
    for (int k=1; k<=steps;k++)
        fib(9000*k);
    write("%d\n", fib(n));
}